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USB and FireWire Problems and Solutions - Page 1

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Visit the USB and FireWire section of this site for information on those serial standards.

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1. - Windows 7/8.1/10 changes drive letters for USB flash drives that makes backups fail

2. - Information on the most common FireWire problems in the Microsoft Knowledge Base

3. - How to recover USB flash drives and devices that become stuck in read-only, write-protected mode

4. - USB power sources: self-powered devices and hubs and devices and hubs powered via a USB cable connected to the computer

5. - My USB flash drive/memory stick won't work on my Windows 7 PC but does work on Windows XP and Windows Vista PCs

6. - Problems with an external hard disk drive and printer connected to a laptop via a Belkin 7-port USB powered hub

7. - I can't connect an iPod Touch via a USB port to my Windows 7 desktop PC, an error message from which says that the device is not recognised [US: recognized]

8. - Unrecognised/unrecognized USB devices: Example - "USB Device Not Recognized" error message when I try to connect a 500GB USB external hard drive

9. - When I plug my memory stick/flash drive in a USB port or a CD/DVD in the optical drive the window showing the options to display the contents doesn't come up as it used to

10. - I get this error message "Windows cannot Load the device driver for this hardware because a previous instance of the device driver is still in memory. (Code 38)" if I connect two USB devices at the same time

11. - I have daisy-chained several FireWire storage devices to my computer, but some of them are not recognised by Windows XP/Vista

12. - I pushed the FireWire connector into the FireWire port on my PC the wrong way around and fried the iLink board on my camcorder

13. - Common questions about USB connectivity answered AND MS Knowledge Base articles on USB problems

14. - My digital camera won't connect to USB

15. - Clearing the confusion about USB 1.1 Full Speed and USB 2.0 High Speed

16. - Confused about the support for USB 1.1 and USB 2.0

17. - My laptop computer's USB ports don't wake up from standby

18. - My Mustek USB scanner, which is already installed in Windows XP, is recognised (US: recognized) by Windows as new hardware, but it won't switch on

19. - Can Windows XP format my new USB external hard drive?

20. - How can I format an external USB hard drive without having to make it the C: drive?

21. - My external USB hard disk drive works with my desktop PC but it won't work with my laptop computer

22. - How do I format a USB flash drive under Windows XP?

23. - My Windows XP Home Dell Inspiron 8200 laptop/notebook PC/computer has developed a problem reading USB flash drives/memory sticks

24. - Windows XP/Vista/Windows 7 failed to recognise three different flash drives/memory sticks on six different computers/PCs making the data inaccessible

25. - Windows updates and USB driver problem: I can't get Windows 2000 to recognise my computer's USB ports in order to use my printer

26. - Are the USB 1.1 ports of a computer case compatible with a USB 2.0 motherboard?

27. - USB DOS mode and legacy device problems

28. - Will a USB 1.1 motherboard accept USB 2.0 devices? AND USB 2.0 support in Windows XP AND USB 2.0 support in Windows 98, Windows 98 SE and Windows Me

29. - Some USB devices won't work from a motherboard's USB port no matter what you do

30. - A new USB 2.0 PCI adapter card cripples PC - an adapter card chipset and motherboard chipset incompatibility

31. - How things can go wrong with a USB device: an IRQ conflict

32. - Why some USB devices work via a USB hub, while others will not

33. - Problems with a powered USB hub

34. - If the hot-plugging of a FireWire/USB device fails in Windows XP...

35. - Problem: All of a sudden none of a computer's USB ports work

36. - Have I destroyed my motherboard, keyboard and wireless network adapter by using two USB ports at the same time that are linked together on the motherboard?

Click here! to go to Page 2 of USB and FireWire Problems & Solutions

Click here! to go to the full list of hardware and software problems dealt with on this website

Windows 7/8.1/10 changes drive letters for USB flash drives that makes backups fail

If you use USB flash drives to store backups, you might have discovered that Windows 7/8.1/10 can assign a different drive letter to a particular drive used at different times. For example, when you stored the backup, Windows assigned the drive letter F: to the drive, but when you used the same USB port, the drive was called the E: drive, consequently Windows produces an error message and backing up to it fails.

This happens because Windows doesn’t assign a permanent drive letter to a particular USB port, it assigns drive letters according to the mix of drives attached to the computer at a particular time. For example, you may have added or removed another USB drive. If the drive letter of a USB drive was F: and then changed to E: using the same USB port, no doubt you removed a USB drive from another USB port, which forced Windows to drop a letter. It would not matter which USB port the flash drive was inserted into, because, in alphabetical order, Windows assigns the next available letter to it. In this example, Windows had probably made the main hard disk drive the C: drive and the CD/DVD drive the D: drive. There were no other drives installed, so when you inserted the flash drive it was made into the E: drive. If you inserted another USB drive, it would be made into the F: drive. That has to happen because Windows does not assign drive letters to USB ports.

Note that in dual-boot and multi-boot systems of different operating systems, which could be versions of Windows or other operating systems, such as distributions of Linux, Windows always makes the boot drive the C: drive so that when you create backups the different operating systems are always backed up so that they always have the same drive letters. For example, you might have Windows 7 installed on the C: drive and then you installed Windows 10 and it installed itself on the D: drive, making the CD/DVD drive the E: drive. If you boot into Windows 10 at startup, it assigns itself the C: drive and makes Windows 7 use the D: drive. Windows 7 will use the C: drive if you choose to boot with it and Windows 10 will use the D: drive. The CD/DVD will remain using the E: drive. A USB drive inserted into that mix will be made the F: drive. The next available drive letters will be G: and H:, etc.

If you create a backup that assumes that the target USB drive will always be the F: drive, but Windows changes the drive configuration, making the backup drive the E: drive, the next backup to that drive fails because there is no F: drive.

The easiest way to fix the problem is to have the same drives installed when a particular backup was created. In this case, remove the drive assigned the letter E, insert another USB drive in any USB port, which will be made the E: drive and then insert the backup drive that will be made the F: drive.

It is also possible to force Windows to assign a particular drive a particular drive letter. Remember that you can find any part of Windows 7/8.1/10 – apps, programs, Device Manager, Disk Management, etc. – by typing its name in the Search… box and then clicking the link to it provided above the Search box.

In the example used here, insert the backup USB drive, type diskmgmt.msc in Windows Start… box – or in a MS DOS Command Prompt window that brings up the Disk Management window. Identify the E: backup drive, right-click on its entry and click on the Change Drive Letters and Paths option. Use the Change option to reassign the backup drive its original F: drive letter. Note that if you format the drive – using the Format option provided when you right-click on the drive in Disk Management or Computer – and assign it the letter Z and then create your backups to it, the drive letter will not be changed by Windows because there is no higher drive letter and Y will never be used.

Windows tries to remember every USB drive that you have used, which could be part of the problem if you have allowed many drives to be used over the life of the computer. Doing the following fixes most USB problems by rebuilding the USB system and should get rid of any problem. Drives that were once used will no longer be remembered.

Detach all of the USB devices – printer(s), hub, external hard drive, USB network dongle, flash drive(s), etc. If you have non-USB keyboard and mouse use them instead. Enter the Device Manager – in the Control Panel in Windows 7/8.1/10 – scroll down to the Universal Serial Bus controllers (USB controllers) entry, open all of the entries, right-click on each of them and choose the Uninstall option. Next, re-attach the USB devices in the order of their importance – keyboard, mouse, printer, external drive, flash drives, USB dongles, etc., making a note of where they are attached. Then reboot the system, which makes Windows rebuild the USB system. Alternatively, in the Device Manager, after you have uninstalled the devices and re-attached them to the system, click on Action => Scan for hardware changes, the doing of which rebuilds the USB system without rebooting.

Windows Device Manager showing the Universal Seral Bus - USB controllers

How to recover USB flash drives and devices that become stuck in read-only, write-protected mode


Three standard 16GB or 32GB USB flash drives I own have mysteriously made themselves read-only write-protected. They can't even be formatted. The files on them can be seen but can't be deleted, moved or updated. When I try any of those actions, a message comes up saying that the write-protection has to be removed in order to continue.


Flash drives (aka thumb drives and several other names) or any other type of device that uses flash memory, such as smartphones and cameras, can become inaccessible due to a number of causes. There are also a number of things that can be tried to make them usable again.

Some USB flash drives,especially older models, have a write-protect switch that is usually small and placed where it is least likely to be engaged accidentally, such as the narrow end opposite the connector. Examine the drive and it you find one, push it into its alternative position.

The file attributes of all files on the drives may have somehow been changed to read-only (r), hidden files (h) or been designated as system files (s). You need to make use of the Command Prompt from an Administrator account (not a user account) to change those file attributes into their opposite states of write, unhidden and non-system. In Windows XP, if you are running it from its Administrator account, just enter the command cmd in the Start => Run box to bring up the Command Prompt and then type the following command at the prompt's > and press Enter. The minus signs remove the attributes. To get them back you would use the command with + signs instead. To find out about all of the switches that the attrib command uses enter attrib /? at the Command Prompt. If the flash drive has been given the letter G (it could be F, H, etc.,depending on the number of storage drives the system has) the command is:

attrib -r -s -h G: /d /s

If you need to know how to open a Command Prompt from an Administrator account in Windows Vista, 7 & 8, use the web-search query: open a command prompt in windows Vista/7/8 (use your version of Windows only). Here is a suitable link I found for Windows 7:

If the problem still persists for an affected drive, check the Security settings. From an administrator account, open Windows Explorer by right-clicking on the Start button (or File Explorer in Win8 by typing that name while on the Start screen) and then right-click on USB drive. Select Properties and open the Security tab. Note that to get the Security tab, the drive has to be formatted to use the NTFS file system, not FAT32 or exFAT. All of my flash drives have been formatted to use the FAT32 file system in the factory. To format one to NTFS means having to delete all of the files it contains, so doing that is not an option if you need the files.

The settings are self-explanatory. Every flash drive I have has had its security settings set for unrestricted access by default. If that is not the case, clicking the Edit button allows the settings to be adjusted.

If that measure was unsuccessful, run CHKDSK, the hard-drive diagnostic tool provided by all versions of Windows since XP, which might correct the problem. The best way to do so is to run it from the Command Prompt that you used to change the file attributes, described above. Just enter the command chkdsk /? to be provided with the switches you can use. Just entering chkdsk runs the tool in read-only mode that runs and reports on three tests without being able to make any changes to the drive. Running the command g: chkdsk /r, where Windows has given the flash drive the drive letter G:, finds and fixes most problems automatically. Open My Computer in XP and Computer in Vista and Win7 to find out which drive letter has been assigned to the drive. In Windows 8, from the Start screen, just type computer and then click the link called that that is provided on the new screen that comes up.

If you need more detailed information on chkdsk, visit the following page on this website:

If the problem still exists, try modifying the Registry key that controls storage policies. Note that editing the Registry wrongly can render Windows unbootable, so always create a restore point in System Restore before doing so. If Windows can't boot into normal mode press the F8 key repeatedly at startup to bring up the boot menu that contains Safe Mode and Safe Mode with Networking that allows web access.

Visit the following page on this website to find out how to activate the Refresh and Reset system-recovery options and boot the system into Safe Mode, which, in Win8, requires doing much more than just pressing the F8 key repeatedly at startup just before Windows starts to load and then choosing Safe Mode or Safe Mode with networking from the boot menu that comes up.

If the relevant key, discussed below, has a 0 (zero) setting the drive will be able to read and write data; a setting of 1 makes it read-only.

To open the Registry Editor, enter regedit in the Run box (for XP) and in the Search boxes for Visa and Win7. In Windows 8, press the Windows key (the one with a flag on it) and the R key to bring up the Run box. Navigate to the following key:

HKEY_Local_Machine => System => CurrentControlSet => Control => StorageDevicePolicies

If the StorageDevicePolicies key is not there, create it by right-clicking Control, then select New/Key and give the new key the name StorageDevicePolicies (exactly as is). In the left-hand pane, select the StorageDevicePolicies key. Right-click on an empty area in the right-hand pane and select New/DWORD, call the new DWORD WriteProtect (exactly as is) and press Enter. Right-click on the new DWORD, click Modify and give it a value of 0 (zero). If StorageDevicePolicies is already on your system, but WriteProtect has a value of 1, right-click on WriteProtect and change the value to 0 (zero). If WriteProtect doesn't exist, it can be created in the same way described above for the creation of StorageDevicePolicies.

If even that option fails, try the free Apacer LFormat Utility. According to reports on the web, it can format even locked thumb drives.

If none of the above options work, it looks as if all of your flash drives have somehow failed and will have to be replaced. If the files on them must be recovered, there are many file-recovery companies that can be researched on the web. Do your research well, because data-recovery is usually expensive.

It's a good idea to use a short USB extension cable to connect USB drives to instead of directly to the connectors on the computer, because doing so makes it less likely that damage will be done to the drive when it is removed and the computer's connectors won't be used all the time, reducing the chances of damaging them.

USB power sources: self-powered devices and hubs and devices and hubs powered via a USB cable connected to the computer

A USB cable provides a data transfer connection and provides power to the device.

USB devices are either powered via the USB cable that connects them directly to the PC or laptop, such as wired or wireless mice and keyboards, flash drives, cameras, mobile phones, etc., or by an independent power supply supplied with the device that connects them to the mains electricity supply, such as external hard disk, external CD/DVD drives, printers, scanners, MFPs, monitors, etc.

Each USB port provided by a computer can connect a single device or a non-powered or a self-powered hub to which several USB devices can be connected. A non-powered hub just splits access to the port to as many USB ports as it provides. If the hub connected to a single USB port has four ports, four USB devices can be connected via it. A self-powered hub is just like a self-powered USB device, such as a printer, with its own power supply. It adds additional USB ports but also provides their power.

Self-powered hubs usually provide up to 500 mA (milliamps) of power to each of its ports, while non-powered hubs split the total 500 mA provided via the USB cable attached to the port among all of ports and the hub itself, which can draw up to 100 mA.

If too many non-self-powered, power-hungry devices (not including self-powered printers, external drives, etc.) are connected to a non-powered hub, collectively they can exceed the maximum of 500 mA made available from the computer. Therefore, if you have problems with many devices connected to a non-powered hub, try using a self-powered hub.

Windows 7 provides a way to find out how much power is available per USB port. To access that information, open the Device Manager by typing device in the Start => Search.. box and click the link called Device Manager. Scroll down to the last of the devices and open Universal Serial Bus controllers. There should be several items called USB Root Hub. Right click on any of them, click Properties in the menu that is presented and open its Power tab. You should see Total power available: 500 mA per port.

So, if you had everything working from, say, a non-powered hub and then when you add another device and things start to go wrong, check that the maximum power limit for the port has not been exceeded by the addition.

My self-powered HP PSC 1410 printer-scanner-copier registers as using only 100 mA.

View USB Power and Bandwidth Allocations for a Device [Windows 7] -

HP Notebook PCs - USB Device Troubleshooting (Windows Vista) -

Advanced troubleshooting tips for general USB problems in Windows XP -

My USB flash drive/memory stick won't work on my Windows 7 PC but does work on Windows XP and Windows Vista PCs


My 8GB USB flash drive works as it should on a Windows XP and a Windows Vista PC and on a Windows 7 laptop, but won't work on my Windows 7 desktop PC. It does not report a problem and reads other flash drives, such as earlier, lower-capacity models I have. I have tried plugging it directly into a USB port instead of into a USB hub, but with no luck.


Flash drives can be annoyingly inconsistent in ways such as the one you are experiencing. I know of someone who had six drives that all failed irrecoverably during use, so don't ever use a flash drive as your only backup source. Note that there are many free online storage providers, such as Microsoft's SkyDrive that provides 7GB of free storage to anyone with a Windows Live ID, which anyone has who has a Hotmail email account. SkyDrive is accessed from within the Hotmail account.

When removing a drive always pull it straight out without putting any sideways pressure on the connector, which can be weakened fairly easily, and don't leave it inserted in a front port where it can be brushed against, stepped on, etc.

If a USB port in not able to deliver enough power, the drive can't be initialised, so try plugging it into a USB port at the back of the computer, because the ports at the back usually have the highest power output. If you plug it into a USB port provided in the front of the case, remove any other USB device also connected from there to ensure the maximum amount of power can be drawn. If doing that doesn't work, if you were using a non-powered USB hub, try using a powered model that comes with its own power adapter. You will probably find the cost of doing that not worth while when you could just buy another flash drive that will no doubt work instead. Sometimes there is nothing that works to get a particular flash drive to work on a particular computer. I have come across a PC that would not work with several flash drives. If you can't get flash drives to work on that PC and you need to use one, the cheapest solution would be to replace its motherboard with one that is compatible with the existing RAM memory and processor. I recommend motherboards made by MSI, Asus and Gigabyte, none of which have given me any incurable problems.

Problems with an external hard disk drive and printer connected to a laptop via a Belkin 7-port USB powered hub


I have an elderly HP Pavilion Dv5000 laptop PC that came with Windows XP preinstalled but is now upgraded to run Windows 7 Home Premium. I use a Belkin 7 port USB powered hub to connect an external hard disk drive, a Lexmark printer and a scanner. Everything was running flawlessly until recently when the laptop started having problems with the connection to the external hard drive. The printer has also began acting up occasionally. Is it time for me to get a new laptop?


The chances are excellent that the problems with those USB peripheral devices have nothing to do with the laptop. USB hubs can be the cause of problems of this kind, due mainly to device-driver or insufficient-power issues. If updates are available, you could try updating the drivers for the specific makes/models of USB devices from their manufacturers' websites and the USB driver itself from the laptop manufacturer's website. If doing that doesn't work, that HP laptop has two or three USB 2.0 ports depending on the model, so instead of connecting them via the hub try connecting each device to its own USB port. If the laptop only has two USB ports, perhaps your Lexmark printer has wireless capability and can be connected wirelessly to the laptop and you can use the two USB ports for the hard drive and scanner. Alternatively, you could just connect a USB device to the laptop when required.

Unrecognised/unrecognized USB devices: Example - "USB Device Not Recognized" error message when I try to connect a 500GB USB external hard drive and USB flash drives

"The 'USB Device Not Recognized' error message is probably familiar to many users of USB device, who have probably overcome the problem by unplugging and relugging the device until it is recognised. However, this did not work with a 500GB external USB hard drive, which I tried to connect to several PCs, all of which produced that error message.

"I did the MS troubleshooting, and always got to the "Replace the device" recommendation at the end of the troubleshooting process. I swapped out USB cables numerous times with cables I'd been using for years. Then I did what seemed like weeks of research on the Web and was about to give up when finally I found a forum that suggested buying a new cable. Per the forum, this one suggestion seemed to have helped literally hundreds of people. I did just that. A new heavy-duty cable ... solved all the issues I'd been having, and the two drives came to life with no problems since. All of the other USB devices I'd been having trouble with over the years now work as if nothing had ever been wrong. They are now all recognized on the first plug-in. "I might also mention I've always been an advocate of using the Safely Remove Hardware program (from its icon in the bottom right-hand corner Notification Area which only appears when USB devices are installed) before disconnecting a USB device, so that was not the issue, either. Just wanted to pass this along, as it has saved me much heartburn. And to think I almost tossed some of these devices."


It's not just cables. USB flash drives are also prone to this kind of failure. It comes from the mechanical flexing of the plug, which can crack the soldered electrical connections inside the cable or USB device. Depending on how the device or cable is inserted into the socket, the cracked connections may or may not make contact and conduct electricity, which is why this can appear as an intermittent problem. Once the solder connections are broken, there's no practical way to fix them. Your best bet is to prevent the problem from the start. Whenever you plug in any USB hardware - including cables - make sure you grip the device solidly where it's meant to be gripped. Insert and remove the device perpendicularly to the socket, with no sideways or up-and-down forces. Don't wiggle the device to insert or remove it. Straight in, straight out, and you'll avoid the most-common kind of USB connection damage!


The DevCon command-line utility functions as an alternative to Device Manager -

"The DevCon utility is a command-line utility that acts as an alternative to Device Manager. Using DevCon, you can enable, disable, restart, update, remove, and query individual devices or groups of devices. DevCon also provides information that is relevant to the driver developer and is not available in Device Manager. You can use DevCon with Microsoft Windows 2000, Windows XP, and Windows Server 2003. You cannot use DevCon with Windows 95, Windows 98, or Windows Millennium Edition." -

After you plug in a USB device that gets ignored, run this program. The 'rescan' option causes the system to rescan the USB ports, which usually results in a USB device being acknowledged and becoming usable. -

When I plug my memory stick/flash drive in a USB port or a CD/DVD in the optical drive the window showing options to display the contents doesn't come up as it used to

Usually when you plug a USB flash drive/memory stick or insert a CD/DVD disc into your laptop or desktop PC, a window comes up that displays several options that can be chosen from to display the contents of the drive or disc. You usually choose the Open folder to view files option in order to view the contents. If that window no longer presents itself, to fix the problem try using the Autoplay Repair Wizard:

"The Microsoft AutoPlay Repair Wizard scans your computer devices to find defective AutoPlay settings, and attempts to fix those it finds." -

You basically insert the USB flash drive or CD/DVD disc and run the program, which allows you to select the problem device, and then when prompted, remove then re-insert the drive or disc. The instructions are very straightforward and the whole process does not take long.

I get error message "Windows cannot Load the device driver for this hardware because a previous instance of the device driver is still in memory. (Code 38)" if I connect two USB devices at the same time


I have a Canon PowerShot A720 IS digital camera and an elderly Mustek 1200 USB scanner, which is works perfectly well. However, if I connect the camera to any USB 2.0 port on my Windows XP Professional desktop PC, the scanner must be disabled in Device Manager, otherwise I get error message: "Windows cannot Load the device driver for this hardware because a previous instance of the device driver is still in memory. (Code 38)". I could transfer photos to my PC using my SDHC card reader, and continue disabling and enabling the scanner, but it seems daft to me that I have to do this when USB is supposed to be able to connect over a hundred USB devices. As is par for the course with most IT support I have used, Canon's support were of no use. I have looked for an answer on the web and it seems that this is a common problem.


This is the information on the error message on Microsoft's site: in an article called Explanation of error codes generated by Device Manager in Windows XP Professional: "Code 38 Windows cannot load the device driver for this hardware because a previous instance of the device driver is still in memory. (Code 38) Recommended resolution The driver could not be loaded because a previous instance is still loaded. Restart the computer." -

Unfortunately, restarting the computer doesn't work. Windows XP uses a Twain driver for USB devices called usbscan.sys, which can only support one device at a time. Microsoft probably reasoned that a user would only ever need one scanner, forgetting that any other image-acquisition devices connected by USB, such as cameras and specialised film scanners, have to use the same driver.

The solution is to unplug the scanner before you connect the camera. Microsoft has advised users to unplug the device that you aren't using and then reboot, but usually all you have to do is unplug it. Of course, you can also disable the conflicting device in the Device Manager, which you are already doing. Microsoft has removed Knowledge Base article 324756 that dealt with this problem, which usually means that the problem has been fixed, but reports show that it still exists in Windows XP SP3 and Windows Vista .

Here is the article that deals with it in Windows Vista:

After you resume a Windows Vista-based computer from standby, a bus driver is not loaded as expected, and error code 38 is reported -

I have daisy-chained several FireWire storage devices to my computer, but some of them are not recognised by Windows XP/Vista


I have connected several FireWire storage devices to my computer by daisy-chaining them together, but some of them are not recognised by Windows.


Make sure that you are daisy-chaining the devices properly. Here is the relevant information about daisy-chaining FireWire devices.

If a computer only has a single FireWire 400 port, several FireWire 400 devices can be connected by daisy-chaining them together. Most FireWire peripheral devices have two six-pin FireWire 400 ports making it possible to connect the first device to the computer, a second device can then be plugged into the first device, a third device can be plugged into the second device, etc.

However, if a particular device has a smaller four-pin port, or one four-pin and one six-pin port, instead of two six-pin ports, then it has to be the last device in the daisy chain.

FireWire 400 and FireWire 800 can be daisy-chained by making use of an adapter cable. However, they will then all operate at FireWire 400 speeds.

Is FireWire 800 backwards compatible? -

Question: "I have three FireWire 400 devices, which all run simultaneously, but I only have one FireWire 400 port, so using them all puts stress on the FireWire bus. However, I have a FireWire 800 port which is completely unused. Will my FireWire 400 gear work on the newer standard? If not, are there workarounds?"

Answer: "FireWire 800 devices use a nine-pin connector, and if you need the maximum throughput you have to connect a FW800 device via a nine-pin to nine-pin FW800 'Beta' cable to a FW800 port, and run them in 'Beta' mode. On the other hand, FW400 devices use six-pin (powered) or four-pin (unpowered) connectors, although it's easy enough to buy nine-pin to six-pin or nine-pin to four-pin 'bilingual' cables so you can plug a FW400 device into a FW800 port (or vice versa) and run it in backward-compatible legacy mode." -

Perhaps you are not using an adapter cable between 400 and 800 devices.

FireWire 400 to 800 adapter -

"Use your existing FireWire® 400 cables with this FireWire adapter from Sonnet to connect FireWire 400 devices to a FireWire 800 port, without going through the trouble of purchasing yet another cable. Just plug it in between a FireWire 800 port and a standard FireWire 400 cable's 6-pin male connector (the other end of the FW400 cable plugs into your FireWire device). It can't get any simpler." -

Sonnet FireWire 400 to 800 Adapter (FAD-824) -

If you are using Windows XP with Service Pack 2, make sure that the following hotfix - - is installed, because it fixes a 1394b (FireWire 800) bug that results in both FireWire 400 and FireWire 800 devices running on greatly reduced speeds. If you have Windows XP SP3 installed it is incorporated in it, so there is no need to install it.

You can check which updates have been installed by opening Add or Remove Programs in the Control Panel. Make sure that the option called Show updates is enabled.

I pushed the FireWire connector into the FireWire port on my PC the wrong way around and fried the iLink board on my camcorder


When I connected my Sony camcorder to my PC's FireWire port the other day, somehow I managed to push the connector into the port the wrong way around. Doing that fried the camcorder's iLink board (iLink is Sony's name for its FireWire connection), and caused damage that is going to be very expensive to repair. Surely it shouldn't be possible to push a connector that is square on one side and U-shaped on the other side into its port the the wrong way around. In any case, I have never read any warnings that say that doing what I did is so easy to do.


Unfortunately, that is quite a common occurrence. There are reports on the web of Apple laptop computers smoking when a FireWire connector is inserted into one the wrong way round. As you said, it shouldn't be possible to push a connector that is square on one side and U-shaped on the other side into its port the wrong way round, but if a FireWire cable is made of cheap materials it can have a metal covering that is easily bent or which can come loose, thereby making it fairly easy to insert the connector into a port upside down. The FireWire power connector does that damage because it typically carries a voltage of 25V, which can cause serious damage to circuits that are designed for much lower voltages. Even pushing the connector in at an angle the wrong way round can make a data line short against the power connector. The small FireWire used by video cameras does not include a power pin, because the camera doesn't take power from the PC, it runs from its own power source. However, the problem you have described occurs when the data lines connect with the power connector in the computer's FireWire port.

It is far too easy to insert the connector into the PC's port at the back of the case partially at an angle or the wrong way round. Therefore, you should always turn the computer off and plug the FireWire cable into the computer before plugging it into the camera. The FireWire standard's specifications say that FireWire devices can be hotplugged or are hot-swappable (can be plugged in while the computer is running), but any reputable data-recovery business will be able to tell you that many external FireWire hard disk drives are sent in for data recovery after having their circuitry fried by being hotplugged into a computer. It is therefore, also not advisable to hotplug (hot-swap) external FireWire hard drives. You should plug them in before the computer is switched on.

Note well that it is also possible to fry equipment that is connected by a FireWire cable that is kinked or that is damaged and which is shorting internally. It is therefore always a good idea to throw away a FireWire cable that is starting to look twisted or worn.

Common questions about USB connectivity answered AND MS Knowledge Base articles on USB problems

If you don't find a problem that fits yours, click any article's Knowledge Base number and conduct your own search from that problem's page using its Search box by entering a suitable search query the describes the problem.

FAQs on USB (Universal Serial Bus)
USB 2.0 support in Windows XP Read this article: USB 2.0 Support in Windows XP: High Speed at Last. If you are still unsure if Windows XP on your PC supports USB 2.0, read this article: How to Check for High Speed USB (USB 2.0) Support
USB 2.0 support in Windows 98 and Windows Me

You can use a generic USB driver for USB storage devices for Windows 98 that were written by a German programmer called Maximus Decim. It works with a wide range of USB storage devices. There is no home page and no support. To find download sites, you have to enter the man's name in a search engine. I found the following page that might not exist when you click on its link. If so, try entering the man's name in a search engine.

Windows 98 USB Mass Storage Device Drivers -

Click here! to go to more information on this site on using USB 2.0 in Windows 98 and Windows Me

Windows98 SE USB Guide -

How do I connect a camcorder video output to a USB port? Use a USB-to-Video or S-Video adapter cable
How do I add USB ports to my Mac or PC? Install a USB controller card that contains USB ports in a PCI slot in your Mac or PC
How do I network computers with USB ports in order to share files and peripheral devices? Install wired or wireless USB network adapters in all of the computers to create an Ad Hock network, or add a wired/wireless switch/Access Point or router to create a peer-to-peer network, or use a USB network cable
How do I connect a device that is more than 16 feet from my USB hub? Use an "active" repeater extension cable that has an inbuilt repeater that increases the strength of the signal
How do I use a USB port to connect a computer to a wired Ethernet network? Use a USB-to-Ethernet adapter
How can I connect a parallel-port printer to a USB port? Use a USB-to-Parallel (IEEE-1284) converter cable
How do I connect my PS/2 mouse and PS/2 keyboard to a USB port? Use a USB-to-PS/2-Port converter cable
How do I connect a serial device such as an external dial-up modem or GPS to USB? Use a Serial-to-USB converter cable
How do I share USB devices between computers? Use a USB switchbox (hub) and as many cables as there are computers
Click the MS Knowledge Base reference number to go to that article

MS Knowledge Base articles on USB problems

USB Device Does Not Initialize at Startup or Windows XP Stops Responding at Startup or Shutdown (830957) - When you start or shut down your Microsoft Windows XP-based computer, either of the following behaviors may occur: A Universal Serial Bus (USB) device (for example, a USB mouse or a USB keyboard) may not initialize when Windows XP starts.
You do not receive notification when the USB bus is overloaded on a Windows XP-based computer - On a Microsoft Windows XP-based computer that uses certain ATI chipsets, you do not receive notification when the USB bus is overloaded. For example, you do not receive notification if the sum of the power requirements for the connected USB devices is more than the available power that is provided by the USB bus.
One or more USB devices may not work after you start your Windows XP-based computer - When you start a Microsoft Windows XP-based computer that has one or more universal serial bus (USB) devices attached, one or more of these USB devices may not work. You do not receive an error message in this scenario. Note These USB devices may be attached either directly to USB ports on the computer or to an external USB bus-powered USB hub...
You experience a delay when you transfer data over a USB port and CPU usage increases to 100 percent on a computer that is running Windows XP with Service Pack 2 - You experience a delay when you transfer data over a USB port on a computer that is running Microsoft Windows XP with Service Pack 2 (SP2). For example, you experience a delay of five seconds before the data transfer is completed. When this problem occurs, CPU usage increases to 100 percent...

My digital camera won't connect to USB


My Packard Bell Easynote L4014 laptop PC runs Windows Vista Home Premium. Whenever I plug my Samsung V700 digital camera into any of its USB ports, an error message appears saying that a USB device attached to the computer has malfunctioned, and the Device Manager says that the device cannot start. I have already installed the latest device drivers for the camera and the laptop's Intel 915GM chipset, but the problem persists.


Intel chipsets have a good reputation with regard to their USB support. In fact, most USB problems are caused by the other makes of chipset.

For anyone who doesn't know how to update the motherboard's chipset device drivers, which control the USB bus, you identify the make/model of your PC's motherboard, find its manufacture's website, find the support/download section and search for the drivers for that model of motherboard. To install the drivers usually involves using a live update procedure that updates the drivers online or downloading the drivers and installing them manually. Instructions are provided on how to install the drivers - either on the website or in a text (.txt) file inside the zip file that contains them. Here is an extract from an installation text file that came in the zip file containing device driver files:

"Important Note: The Intel(R) Chipset Device Software is distributed in two formats: self extracting .EXE files (INFINST_AUTOL.EXE) or compressed .ZIP files (INFINST_AUTOL.ZIP). Depending on which distribution format is being executed, the command-line syntax may differ. Refer to Section 4 for more details."

A self-extracting .exe file is simply clicked on to install its contents; a zip file is opened by clicking on it. Windows Vista and Windows 7 can open zip files, but Windows XP requires a third-party program such as WinZip. A zip file usually contains a setup.exe file that you click on to install the drivers. The zip file's contents may have to be extracted to a specific folder so that the Update Driver feature for a particular device, such as the graphics card (under Display adapters) can be run from within the Device Manager.

The first action you should take to resolve a USB problem is to disable the Save Power option in the Device Manager for the each of the USB Root Hub entries. Up to five entries called USB Root Hub can appear under Universal Serial Bus controllers. Open the Device Manager by entering devmgmt.msc in the Start => Start Search box. Open each of the USB Root Hub entries and disable the Save Power option under the Power Management tab by removing the check mark that enables it.

The USB device has malfunctioned error message most commonly appears when a USB device is drawing power close to the maximum limit for USB connections. Many laptop computers don't provide enough power for the most demanding devices.

Simply disconnecting and then plugging the device in again often works. You could also try connecting a device that uses less power, such as a USB modem, and then connect the camera while the other device is still connected. Doing that seems to make the USB bus ready to receive the more demanding device.

If none of those solutions work, try connecting the camera a self-powered USB hub that has its own power supply and provides several USB ports by connecting to one of them on the computer. (Some simple USB hubs are powered via the USB connection.) Buy only a high-quality brand-name USB hub, such as the Belkin Hi-Speed USB2 4-Port Hub, because cheap hubs can themselves be a source of problems.

Clearing the confusion about USB 1.1 Full Speed and USB 2.0 High Speed


I'm by no means an expert when it comes to PC's and related tech (i.e. I'll never work in the industry), but I do build my own PC's, install software, and do my own troubleshooting (well some of the fixing amounts to just swearing at the PC).

However, today I made a fundamental error, which I partially blame on the people/organisations, etc., (or Canon!). which came up with the nomenclature for the various USB speed ratings. As an example, I've just bought a Canon LiDE30 flatbed scanner, which has a USB 2.0 interface (hey it's not USB 1.1 is it?), only it's 2.0 Full Speed NOT (as I now realise, too late) 2.0 High Speed, so, hey, it is USB 1.1.

Of course, I've compounded the error by buying a 2.0 High Speed PCI card, so I'm reasonably annoyed with myself. Now the upshot of all this is that the scanner produces good results but takes its time and I'm wondering why someone just didn't say "We've got USB 1.1 now we're moving up to USB 2.0" instead of this confusing muddle of 2.0 Full Speed (i.e. 1.1) and USB 2.0 (High Speed). Yes I know there's meant to be a 2.0 High Speed logo displayed for these devices but if I can make this mistake so can others make the same one?


There was concern that people would NOT buy 1.1 peripherals to use with their USB 2.0 machines, so, since 2.0 is a superset of 1.1, the names are now "2.0 High", "2.0 Full", and "2.0 Low" instead of "2.0", "1.1 High", and "1.1 Low".

Confused about the support for USB 1.1 and USB 2.0


I have heard about USB 1.1 and USB 2.0. How can I identify which of these versions is supported by my computer?


USB specification version 2.0 is an upgrade of USB 1.1. The new standard provides additional bandwidth for multimedia and storage applications, and also offers plug-and-play (PnP) capability, and full backward compatibility for legacy (1.1) USB devices. USB 2.0 includes everything that USB 1.1 offers, and adds a high-speed mode, which runs at 480 megabits per second (MBits/s). USB 1.1 supports two speed modes (1.5MBits/s and 12MBits/s), whereas USB 2.0 has three of them: 1.5, 12, and 480MBits/s. USB 2.0 uses the same 1.1 compliant cables to connect high-speed devices. However, classic USB (1.1) hubs will slow down USB 2.0 devices. A USB 2.0 host controller is required to enable the high-speed connection with a USB 2.0 device. If one is not supported by the motherboard a PCI adapter card that supports it can be installed. Plugging a USB 1.1 device into a USB 2.0 hub is fine, but connecting a USB 2.0 device to a USB 1.1 hub is prohibited. USB 1.1 devices won't run any faster on a USB 2.0 hub, but they can work with USB 2.0 devices on the same bus. USB 2.0 won't replace USB 1.1 because many products such as generic keyboards, mice, joysticks, and audio speakers do not require the faster speed of the new technology, which is also more expensive to install on motherboards.

Pressing the WinKey + Pause/Break keys opens the System Properties window. The Device Manager is located under different tabs in the different versions of Windows (for example, it is under Hardware in Windows XP). Under Device Manager, look for the Universal Serial Bus. If there is no "Enhanced" expression used to describe the USB Controller, you have the older USB 1.1 version installed.

My laptop computer's USB ports don't wake up from standby


Sometimes the USB ports on my Toshiba Tectra M5 notebook, which runs Windows XP SP2, won't wake up from standby mode when the system does. My USB mouse and printer don't work. I have to restart the system to get them working. I have done some research on the problem by using various search terms in a search engine. Apparently, the the problem occurred in Windows XP SP1, and were supposed to have been fixed by the SP2 update.


It is not uncommon to discover that a PC or laptop computer has a problem when resuming from power-saving modes of operation, such as standby mode. These problems can often be fixed by reflashing the BIOS with an update that has been programmed to put known problems right, or by updating the motherboard chipset device drivers, downloaded from the computer's motherboard manufacturer's or the computer manufacturer's site, or by updating other software that is installed, such as the power-saving and fingerprint-recognition software used in laptops.

Your computer is one of the early Intel Centrino Duo notebooks, and there is a known problem that can prevent the system from using power-saving modes of operation when it is connected to a USB device. Attempts to fix that problem in the BIOS, motherboard device drivers, or other software, might have been the cause of the problem that you are experiencing.

Doing nothing more than updating the BIOS should fix the problem. Make sure that you install the latest BIOS for that particular model of the Toshiba Tectra M5. Check the model number to make sure that you install the correct BIOS update. If you don't know how to install the update, Toshiba's site should provide you with the necessary information for that model. The process usually just involves downloading the update utility, which you then run from your system. It downloads the update and installs it when the system is rebooted.

If doing that doesn't fix the problem, try downloading and installing the latest Intel motherboard chipset drivers for that model, and Toshiba's Power Saver and Fingerprint software, all of which should be made available by Toshiba's support site. Bugs in the Fingerprint software that cause that sort of problem have been reported on the web.

My Mustek USB scanner, which is already installed in Windows XP, is recognised (US: recognized) by Windows as new hardware, but it won't switch on


My trusty Mustek USB scanner won't power up. When I start up my PC that runs Windows XP, a message saying New hardware detected comes up, followed by another message that says Unknown USB device installed. This must be to do with the scanner, which is already installed and working properly according to the Device Manager, but it won't switch on. Has my scanner developed a hardware fault, or is Windows at fault?


A New hardware detected message from Windows means that the scanner is receiving power, that the computer is detecting it and telling Windows that it is connected. However, for some reason, Windows fails to recognise that the scanner is already installed, which is a good sign, because the problem is more likely to be caused by a corruption of the Windows Registry than by a hardware failure. In most cases, if the problem were caused by a hardware failure, Windows probably wouldn't have recognised the presence of the scanner. However, if the scanner's firmware, which is the configuring and controlling software that is embedded in it in flash memory, has become corrupt, it could make the scanner send an incorrect device identification string to Windows, which would then issue a New hardware detected message. However, corruption of the firmware in printers and scanners is a very rare occurrence.

An easy way of determining if the scanner is sound would be to connect it to another computer and install its software. The chances are excellent that you should find that the scanner works as before. Note that some printers and scanners require the software to be installed from the supplied CD before the device is connected.

If you can't do that, try using System Restore to restore a restore point that predates the problem. System Restore restores the Registry to the way it was on the date that the restore point was created. If the Registry has been corrupted, restoring it to the way it was on a date that predated the problem would fix the problem.

Alternatively, if the scanner's software is installed after the scanner is connected, disconnect the scanner and uninstall its drivers.

If you don't know how to do that, enter scanners in Windows Help and Support search box and then click Input device troubleshooter (keyboard, mouse, camera, scanner) that appears under Fix a problem. Here is what the Input Devices troubleshooter says about how to do that:

"To remove and reinstall the driver. - Disconnect the device from the USB port. Turn off the power for the device, if it has a separate power supply. Open Device Manager. Double-click the appropriate device category. Right-click your USB device, and then click Uninstall. If your device is not listed, this means that it was uninstalled automatically when you disconnected the device."

Restart the computer and go into Safe Mode by repeatedly pressing the F8 key after the memory count at startup, and open the Device Manager (by entering devmgmt.msc in the Start => Run box) to make sure that there is no entry there for the scanner, which would not appear in the Device Manager in normal mode. If there is any entry there for the scanner, remove it in the same way as you did the first time in normal mode. In Windows Vista, enter devmgmt.msc in the Start => Start Search box to open the Device Manager.

Restart the computer (Start button => Turn off computer => Restart) and connect the scanner. When the New hardware detected message comes up, insert the driver CD that came with the scanner. Windows should then be able to locate and install the drivers from the CD.

If the instructions for your scanner says that the software for the scanner has to installed before connecting the scanner, run the CD that came with the scanner before you reconnect the scanner.

Can Windows XP format my new USB external hard drive?


I have a new 120GB Western Digital Hard Drive installed in a USB 2.0 external case. I need to format it and get it running. I'm using Windows XP.


Windows XP has an Initialize Disk Wizard. If you start Disk Management after adding a drive, the Initialize Disk Wizard appears so you can initialise the disk , partition, and then format it.

But if you have to access the Wizard manually for some reason enter diskmgmt.msc in the Start => Run box or open the Control Panel => Administrative Tools => Computer Management => Disk Management. If an unformatted drive is present it is listed as one of the installed drives, each of which has a small descriptive section. For an unformatted drive the description says Unknown or Not Initialized. Right-click on it and select Initialize Disk, then right-click on the right-hand side of the next window and select New Partition to start the New Partition Wizard. Select Primary Partition and continue with the wizard.

Installing a hard disk drive in Windows XP: "Unfortunately you can't just put a drive in the case, plug it in and it will work. You will need to initialize and format the drive before it will show up in My Computer or Windows Explorer." - Click the link to the following page. It provides illustrated instructions on how to use the Wizard. -

How can I format an external USB hard drive without having to make it the C: drive?


Is there a way to format a new hard drive that I've connected via a USB port? My computer runs Windows XP. I recently installed a 200GB hard drive, then a week later, had to return my 80GB hard drive to the vendor. When it, or a replacement, was returned, I tried to set it up as an external drive in an enclosure with a USB connection, but it wouldn't format. I had to remove the side of the PC case, disconnect my 200GB C: drive , and format the 80GB external drive as if it were my C: drive. Once I got the first half partitioned (partitioned as two drives) and formatted, I reinstalled the 200GB drive as the C: drive, and then was able to format the second partition on the external USB drive. That seems like a lot of trouble to me. Can a brand new, out-of-the-box hard drive (say, a 100 or 160 or 200GB drive) be cabled as an external USB drive, and then be partitioned and formatted without having to make it the C: drive?


How to initialize, partition, and format a new hard disk drive from within Windows XP

With the USB drive connected, enter diskmgmt.msc in the Start => Run box to bring up Disk Management. The drive should be given a space there with the other drives, and you should be able to partition and format if from there by right-clicking on its space. You have to initialise (US: initialize) it in Disk Management before you can format it, but it will be listed there.

Here is what Windows XP's Help and Support says about initialising a disk:

"To initialize new disks: Open Computer Management (Local) [under All Programs => Administrative Tools]. In the console tree, click Disk Management. Right-click the disk you want to initialize, and then click Initialize Disk. In the Initialize Disk dialog box, select the disk(s) to initialize. The disk is initialized as a basic disk. To open Computer Management, click Start, and then click Control Panel. Double-click Administrative Tools, and then double-click Computer Management. You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings might also prevent you from completing this procedure. New disks appear as Not Initialized. Before you can use a disk, you must first initialize it. If you start Disk Management after adding a disk, the Initialize Disk Wizard appears so you can initialize the disk."

My external USB hard disk drive works with my desktop PC but it won't work with my laptop computer


I have an external USB hard disk drive that I bought so that I could use it to backup my laptop and desktop PCs. However, for some reason, it only works from the USB 2.0 ports on my desktop PC.


Windows XP can still find USB devices that are not a keyboard, mouse or printer tricky to deal with. The external USB drive might not be receiving enough power to initialise, so try the following remedy.

Open the Device Manager by entering devmgmt.msc in the Start => Run box, or right-click on My Computer and click Manage in the menu that comes up to access it. Open Universal Serial Bus controllers and double-click on all of the USB Root Hub entries. There should be three or more such entries. Click on the Power Management tab for each one and remove any check mark in the box that has Allow the computer to turn off this device to save power next to it. Then disconnect the drive, restart Windows, and connect the drive.

If doing that doesn't work, the drive may have come with a USB-to-5V cable, which you should use, because it provides more power.

How do I format a USB flash drive under Windows XP?


During a new install of Windows XP Pro, I deleted all partitions seen in the WinXP partition manager, which unfortunately included my 128MB USB flash drive that was left plugged in. The problem is now I have a flash drive that WinXP cannot format. FDISK, of course does not work with WinXP. If I try to format the flash drive using WinXP, I get the message "Windows was unable to complete the format". WinXP sees the drive as FAT32 with an unknown capacity. Why Microsoft decided to make the WinXP partition manager only accessible on a new installation and to do away with FDISK is beyond me.


Who told you that you can only partition and format drive with a new installation? You can partition and format hard drives at any time by using the partitioning and formatting utility that is made available from the Windows XP CD, or you can enter diskmgmt.msc (the quickest way) in the Start => Run box to bring up the Disk Management window and format hard drives and flash drives. USB device drivers are not usually installed until Windows boots fully, and the device has to be running before it can be accessed, so you should use Disk Management to partition and format a flash drive. USB devices can be plugged in while the computer is running. Windows detects the device and installs the drivers.

Here is what XP's Help and Support says about Disk Management:

Using Disk Management

"You might need to have a computer administrator account to perform some tasks. Disk Management is a system utility for managing hard disks and the partitions or volumes they contain. With Disk Management, you can initialize new disks, create volumes, and format volumes with the FAT, FAT32, or NTFS file systems. Disk Management enables you to perform most disk-related tasks without shutting down your computer; most configuration changes take effect immediately. To open Disk Management Open Computer Management (Local). In the console tree, click Disk Management. To open Computer Management, click Start, and then click Control Panel. Double-click Administrative Tools, and then double-click Computer Management. For information about using Disk Management, in Computer Management, click Help on the Action menu."

In Disk Management, the drives and partitions are represented by rectangles, starting with Disk 0, Disk 1, etc. The CD/DVD drives installed are also shown.

Here is what Help and Support says about using it: "Disk Management is easy to use. Menus that are accessible from the right mouse button display the tasks you can perform on the selected object, and wizards guide you through creating partitions or volumes and initializing or converting disks."

That means that you right-click each rectangle that represents a drive or partition on a drive with the mouse to access the available features, such as creating partitions and formatting them. Note that you cannot resize partitions, you can only create them if the disk space is available, or delete them. If you delete a partition all the data will be lost. You need to use a third-party partitioning utility, such as Symantec's Partition Magic, to resize partitions without destroying the data.

My Windows XP Home Dell Inspiron 8200 laptop/notebook PC/computer has developed a problem reading USB flash drives/memory sticks


I have a Dell Inspiron 8200 laptop computer running Windows XP that has developed a problem reading USB flash drives/memory sticks. With a memory stick inserted in a USB port, the Device Manager shows the USB Mass Storage Device to be working, using the Usbstor.sys driver. However, under Disk drives (in Device Manager), there is an exclamation mark against the memory stick and a Code 32 error saying: "A driver ... has been disabled. An alternate driver may be providing this functionality." The driver files are Disk.sys, Drvmcdb.sys and Partmgr.sys. When I looked at the drivers for the hard disk drive, the same three are used. Links that a search engine finds for the driver Drvmcdb.sys comes as part of several CD/DVD-burning and player applications, including Roxio, Sonic and Veritas software. Up to now, I had been using memory sticks successfully. The other USB devices that I use work as they should.


As you discovered, the driver Drvmcdb.sys is part of several different Roxio or Sonic CD- and DVD-burning packages. Veritas bought Roxio from Adaptec and then sold it to Sonic Solutions.

You should be able to uninstall any DVD-burning software by using Add or Remove Programs in the Control Panel. However, I am taking it for granted that the computer can access the hard disk drive, which also loads this driver. Therefore, the driver is unlikely to be the cause of the problem.

It is more likely that the use of some other USB device, such as a camera, has installed an incompatible driver. If that is the case, removing all of the USB-related drivers and allowing Windows XP to reinstall them should fix the problem. However, the Device Manager conceals the drivers for disconnected USB devices, even though they are installed. The menu option called Show Hidden Devices, does not show them; it only shows non-Plug and Play (non-PnP) devices.

To show all of the devices, click Start => Run, enter cmd and click OK. In the command-prompt window that opens, enter the following two commands:

set devmgr_show_nonpresent_devices=1 [press the Enter key]

start devmgmt.msc [press the Enter key]

This should open the Device Manager in a separate Window showing all of drivers for disconnected USB devices. Now choose View => Show Hidden Devices and remove all USB-related devices by clicking on the + beside the main headings, right-clicking with the mouse on the device and then choosing Uninstall from the menu that comes up. Restart Windows and the devices should be recognised and reinstalled as it reloads.

If doing that doesn't fix the problem, you can try editing the Registry with the Registry Editor. If you remove entries that are not meant to be removed, Windows can refuse to boot. You have to remove entries that are related to the CD or DVD software only.

In case something goes wrong, create a System Restore restore point by clicking Start => All Programs => Accessories => System Tools => System Restore and use it to create a new restore point. You can enter Safe Mode by pressing the F8 key repeatedly before Windows starts to load at startup. The boot menu comes up. Choose Safe Mode. When loaded Safe Mode looks works like Windows, but only uses basic drivers. You can access System Restore in it by following the click path above and use it to restore the restore point that you created.

To use the Registry Editor, enter regedit in the Start => Run box. Click on the + signs to navigate to:

HKey_Local_Machine => System => CurrentControlSet

Press Ctrl-F to open the Find window and type in UpperFilters. Place a tick with the mouse in the Values option and click the Find Next button. As each entry appears, press the F3 key to move to the next one. Various entries appear in the right-hand window. For each entry, the Default and Class values tell you the type of hardware to which the entry applies. Do not remove anything related to the mouse, keyboard, or infrared port, or remove the entries for disk drives, which will have UpperFilters for partmgr - the Windows Partition Manager.

Look carefully at the entry for Storage Volumes. If you find anything, use a search engine to find out which software it belongs to and remove anything that is no longer in use.

Repeat the search, looking for values called LowerFilters. Be careful not to remove anything relating to networking or the CD-ROM entries, such as imapi or redbook.

Windows XP/Vista/Windows 7 failed to recognise three different flash drives/memory sticks on six different computers/PCs making the data inaccessible


Windows XP/Vista/Windows 7 has failed to recognise three different USB flash drives tested on six different PCs. This is a common problem because many users have asked for advice about it on the web, but no one seems able to offer any useful information. None of the flash drives had been dropped, exposed to extreme heat, frozen, dropped into liquid, or exposed to a strong magnetic field. One day the drive works; the next day it doesn't. Can you tell me if the data on them can be recovered? If you can shed any light on this problem, you know more about it than the contributors on the web.


It's just an unfortunate fact about USB flash drives - they can be rendered useless at any time. They are complicated devices, consequently there is plenty that can go wrong with them.

If a flash drive doesn't exchange data with the computer when it its plugged into a USB port, there is no way that the data on it can be read. When you plug it in, Windows makes a ringing sound to announce that it has detected a USB device and has installed the drivers for it. Windows XP/Vista then automatically bring up a window showing the contents of the drive. If that does not happen on more than one computer, the drive is an ex drive.

Poorly soldered joints - usually the four connections between the USB connector and the circuit board - poor design and/or poor manufacturing are the most common causes of the problem. These weaknesses can be exacerbated by rough insertion or removal of the device. You should always remove a flash drive by pulling it straight out, taking care not to bend it.

However, flash drives can be incredibly hardy, The Gadget Show on the UK's Channel Five, put flash drives to the test. They ran over them with a car, shot them out of a cannon, and baked them in a soufflé at 400°F. Only the flash drives shot out the cannon suffered because they were broken into pieces, but, amazingly, the others worked just fine and retained their data.

If, say, a user is creating and editing documents on the drive with a word processor, saving the documents every five minutes, the constant writing can wear out the flash memory, because flash memory, unlike the space on a hard disk drive, has a lifespan, which depends on the number of write cycles it can allow. File systems designed for hard disk drives, frequently write to the same sector repeatedly. However, note that there is no limit to the number of times that data can be read from the drive. Such an occurrence could only happen if the flash memory itself is faulty, because each flash storage location should be able to be written to hundreds of thousands of times. Flash drives are supposed to have special anti-wear algorithms built into their device drivers that is supposed to spread data writing, but that provides another factor that can be the cause of problems.

Most flash drives don't have a flexible connector and even if they have a flexible connector they protrude from computer, so any knock against the drive while it is connected will weaken the soldered joints.

In most other cases, the hardware has failed and there is no way of getting data off the drive, other than removing the flash memory chip from the controller board and soldering it on to a new board.

In many of cases of sudden, inexplicable failure, the design of the USB circuitry might have allowed an electrical surge - that doesn't damage any of the other circuitry - to damage it fatally.

In a few cases, the drive is recognised by Windows but it fails to see a valid file system on it - a common problem with compact flash and other camera memory cards. If the initial sector (sector 0) on the flash drive has become corrupted, there is a good chance that the data can be recovered by using low-level software to read the "raw" data from the drive. Unfortunately, the kind of failure that prevents reading sector 0, usually also prevents reading from all of other sectors on the drive.

If a flash drive is not recognised by one computer but works in another, this is usually because of driver corruption. You will have to remove all USB device drivers and then allow Windows to redetect and reinstall them. The Q&A My Windows XP Home Dell Inspiron 8200 laptop/notebook PC/computer has developed a problem reading USB flash drives/memory sticks provides information on how to do that.

You should only use flash drives as a means of transferring data between computers, which means that you will always be able to retrieve the data if the drive fails. In short, never allow the situation to arise that the only copies of files is on a flash drive.

Here is a possible fix that might work. Plug the memory stick into a USB port, right click with the mouse pointer over My Computer, in the window that comes up, click Manage and then Disk Management in the Computer Management window that come up. Is the memory stick recognised in Disk Management? - Because it will often show here even if it cannot be recognised in Windows. If it is not there, try using another USB port. If it appears there, right click the memory stick's drive letter under the Volume heading. Click on Change Drive Letter and Paths, click on the Change button and change it to, say, Z, or another letter towards the end of the alphabet. Click Yes when a warning comes up telling you what can happen if you change the drive letter, asking you if you want to go ahead with it. Doing that won't do any harm to the files on the memory stick. Close the Computer Management window and try to access the memory stick through My Computer.

A good way of preventing damage being done to USB flash drives and Bluetooth dongles is to use a cable to connect them instead of connecting them directly to the USB sockets on a computer. Indeed, some memory sticks come with such a cable. I have a memory stick made by PNY that came with such a cable 6 inches long. Moreover, using a cable makes it easier to plug in wide USB devices, especially on a laptop/notebook PC that usually has the plugs close to one another. I have a laptop that has two USB ports on each side with a USB mouse and printer connected to one port on each side. I have memory sticks that are too wide to make use of the free USB ports, so unless I use a cable, I have to remove the printer's cable in order to use it. However, if the device doesn't come with such a cable, you won't be able to buy one of that length, because there are currently none available. Fortunately, any length of USB cable will work, but it has to be a male-to-female extension cable. In the UK, you can buy USB extension cables cheaply (under £5) from

Data recovery is an option if every other option fails, albeit usually a expensive one. In the tests of flash drives on The Gadget Show, the producers sent the flash drive that was shot to pieces to Ontrack Data Recovery's London office. Unbelievably, Ontrack's engineers were able to recover all of the data on the drive.

USB flash drive data recovery -

Windows updates and USB driver problem: I can't get Windows 2000 to recognise my computer's USB ports in order to use my printer


I have a Compaq PC with an AMD K6-2 500MHz processor, running Windows 2000 Pro, and 128MB SDRAM . I have installed a PCI adapter card which has four USB 2.0 ports, and I am unable to get Windows to recognise the USB ports. The Lexmark printer requires a USB 2.0 port to function.


If you haven't already done so, install the latest updates and service packs for Windows 2000, including the post-SP4 Update Rollup, check the USB PCI adapter card manufacturer's site to find out if any special device drivers or settings are required for use under Windows 2000, and, if they are available, download the motherboard chipset drivers from its manufacturer's website.

With PCI USB 2.0 adapter cards, I have found that I usually have to install the USB 2.0 controller manually. Open the Device Manager and look for an Enhanced Host Controller under the Universal Serial Bus controllers heading.

Click here! to see an image of the USB 1.1 and USB 2.0 devices listed in the Device Manager.

If there is an Enhanced Host Controller shown in your computer's Device Manager, you have USB 2.0 support installed. If not, you have to install the controller by installing the drivers for the motherboard from its website. If you install the motherboard's chipset drivers the controller will show the chipset manufacturer's name - e.g., VIA USB Enhanced Host Controller, where VIA is the chipset manufacturer. If Windows installed its USB 2.0 controller it is called the Standard Enhanced PCI to USB Host controller.

Windows XP and Windows 2000 had USB 2.0 support added by the Service Packs. It is supposed to be installed automatically, but, as I said, I have found that I usually have to install the USB 2.0 controller manually.

Are the USB 1.1 ports of a computer case compatible with a USB 2.0 motherboard?


You have a computer case that has USB 1.1 ports built into its front. You have purchased a new motherboard that has built-in USB 2.0 ports. The case manufacturer's technical support has told you that the ports will work, but only at USB 1.1 speeds. But the company that built the computer said that the USB 1.1 port connectors in the case are the same as USB 2.0 ports, therefore attaching them to a USB 2.0 motherboard would deliver USB 2.0 performance. You want to known which advice is correct.


The connectors are the same, but USB 2.0 uses a different chipset logic (and more elaborate USB hubs) than USB 1.1. To carry the higher speed of USB 2.0, the USB cables must also have a braided outer shield and twisted pair conductors. Every cable I have seen has this shield. Both of these specifications were recommended in the old USB 1.1 standard. Therefore, if you have the correct cables, which you probably do have, you will be able to connect the case ports to the motherboard, and they will deliver USB 2.0 performance to USB 2.0 peripheral devices.

USB DOS mode and legacy device problems

(1)Your USB mouse and keyboard won't work when you boot the system from a DOS start-up floppy disk, or in either of the DOS modes. And you can't enter the BIOS, because the entry key doesn't work.

(2) You have legacy peripheral devices - a scanner, printer, and an external hard disk drive, but your new computer's motherboard only provides USB ports. You want to know if you can still use these devices with the new motherboard.



DOS is not programmed to know anything about USB devices. This can be a perplexing problem to remedy if, for example, you boot to either of the DOS modes, or start your computer from a DOS start-up floppy disk only to discover that your USB keyboard and mouse won't work. The computer will probably start, but you won't have any way of controlling it. Nor will you be able to enter the BIOS setup program, because the entry key (usually Del) doesn't work.

The special "pass-through adapters" that many manufacturers include with USB keyboards and mice, and which can be purchased separately, allow basic devices to work via USB ports. This is because the connection is straightforward, so the keyboard and mouse will work in the DOS modes (full DOS and DOS in Windows). However, note well that this solution won't work for more complex USB peripheral devices such as an external drive, or a CD burner, because they require full USB support and a "pass-through adapter" can't provide it.

There is no single solution for all of the USB/DOS connection problems, but fortunately there is a solution to each of them.

For example, you may be able to enable DOS support for a USB keyboard through a USB/Legacy option that is available in some computer BIOS setup programs, which are most often accessed by pressing the Delete key, or some other specified key during the first few seconds of the system start-up. You will have to use a standard PS/2 keyboard to open the BIOS setup program. (For obvious reasons, the setting to use a PS/2 keyboard is enabled by default in the BIOS.) Then search the settings that relate to USB. If there is a "legacy" option available to you (usually under a Peripherals heading), such as the one described below (copied from a BIOS manual), enable it, and you will be able to use a USB keyboard.

"USB Keyboard Legacy Support Set this option to Enable or Disable USB keyboard/mouse. The Optional and Fail-Safe default settings are Disabled".

Yes, simply enabling that one option should allow you to use a USB keyboard and mouse in the DOS modes.

If such an option isn't offered, or doesn't work, try visiting your keyboard manufacturer's website to find out if it offers a DOS USB driver for your make and model of keyboard. Alternatively, your computer's original manufacturer (OEM) setup CDs may also contain DOS-level drivers. They are often included with new computers to enable the use of a USB keyboard or mouse with the DOS-level "system restore" or "system recovery" software that is often provided instead of a Windows CD.

You can discover all kinds of solutions. For instance, I discovered from a computer newsgroup that if you put the hidusb.sys file on your start-up floppy disk, and load it at the A\:> prompt (in DOS mode), the USB mouse works. Hidusb.sys is a Microsoft USB driver originally from Windows 98, but it is also included with later Windows versions. Search your system, or the Windows CD for the file.

Many vendors offer similar files that are specific to a particular device, so check the website of the vendor/manufacturer of any USB device that you are trying to make work in DOS. lists thousands of USB drivers and related files from hundreds of vendors. Alternatively, you can try using the Google search box at the top of this page (enable the Web Search option on the first search page), using the make and model of your product, along with the words "usb dos driver" as the search phrase.


If, say, you have an external modem that needs a serial (COM or RS-232) port to plug into, and your new computer only has USB ports, do you have to sell the modem? The same problem could apply to legacy printers, scanners, cameras, and other devices that connect through a legacy serial or parallel port.

No, you will be able to use the legacy devices, because you can still purchase an add-on PCI card that contains the legacy ports, or you can buy a special adapter that has a USB connector at one end and a classic RS-232 serial socket at the other end. A small, built-in microchip in the adapter converts data from USB format to RS-232/COM format, and vice versa. To use the adapter, you merely have load a device driver into Windows. Windows then detects and uses the adapter as if it were a new ordinary COM port on the system.

Will a USB 1.1 motherboard accept USB 2.0 devices?

USB 2.0 support in Windows XP

USB 2.0 support in Windows 98, Windows 98 SE and Windows Me


Is there any way I can make my USB 1.1 motherboard accept USB 2.0 devices? - I don't have any free PCI slots.


You need a free PCI slot, because you won't have any other way to add a USB 2.0 PCI adapter card to your system.

If you can free a PCI slot to make room for a USB 2.0 card, and it turns out to be problematic, visit your computer/motherboard manufacturer's website to see if there is a BIOS upgrade, since it might enable the computer to handle USB better than the current BIOS, because many of the earlier BIOSes had problems handling USB. The bugs were rectified in subsequent updates.

"Microsoft still doesn't plan to natively support USB 2.0 but will support the standard through add-on drivers."

That was the position with Windows XP before the release of Service Pack 1 (SP1). This Q&A provides the current situation.

[Note that since this was written, SP2 and SP3 for Windows XP were released. SP3 was the final service pack for Windows XP.]


A user has Windows XP Home Edition and has installed all of the updates for it except SP1, which has the drivers for USB 2.0, but the user has read that a lot of users who installed SP1 have their systems bogged down and it runs slower, boots slower, and can be a nuisance. My computer works fine without it. The user therefore wants to know if there is any way to install the USB 2.0 drivers without having to download and install SP1.


USB 2.0 drivers can be obtained from another source. How good the drivers are depends on the manufacturer of the device requiring them. For instance, this VIA USB 2.0 Host Controller has drivers available for download. But, a USB 2.0 controller's support site - usually the motherboard manufacturer's site - could advise the user of Windows XP to install SP1.

If a user knows the make and model of the motherboard's chipset (ALi, Intel, NEC, SiS, and VIA), the drivers should also be made available for download directly from the relevant site.

If a USB 2.0 PCI adapter card (that provides additional USB ports) is being used, it should come with the USB 2.0 drivers.

Note that Windows 98 SE or Windows Me or Windows 2000 or Windows XP is usually required if you want to use USB 2.0 functionality. The Service Packs (released by Microsoft) have to be installed for them, because USB 2.0 was issued after they were released into the public domain. If you don't have these updated versions on the computer, then it will only be able to use the PCI USB 2.0 adapter card, working in the slower USB 1.1 mode.

USB 2.0 support in Windows 98, Windows 98 SE and Windows Me

Both Windows 98 SE and Windows Me (with their Service Packs installed) support USB 2.0, but only if you install the "OrangeWare" drivers. Microsoft does not supply drivers for USB 2.0 in Windows 98 SE or Me, as the article at the following link states, but third parties do. -

The manufacturer of a USB 2.0 PCI adapter card will list the operating systems that are required to use it. For example, Belkin says that Windows 98 SE is the earliest version of Windows that supports its FSU219 Hi-Speed USB2 dual-port PCI card. In short, Windows 98 (first edition) can't be used to run it.

Various problems with USB support were found in the first edition of Windows 98, so Microsoft rewrote the USB drivers for Windows 98 SE. Unfortunately, the Service Pack that Microsoft created for Windows 98 users, did not include the improved USB driver support. Consequently, many manufacturers of USB 2.0 cards don't support the first edition of Windows 98, and many manufacturers of USB devices, such as digital cameras, claim that Windows 98 SE is the earliest version of Windows that they can run on. However, there are some such cards made by D-Link and IOGear that are compatible with Windows 98 first edition. Therefore, if you want USB 2.0 support, either buy one of these cards, or upgrade to a later version of Windows. If your system is elderly, it is not advisable to upgrade to Windows XP, because of BIOS and other problems, so Windows 98 SE is the version you want.

Some USB devices won't work from a motherboard's USB port no matter what you do


It is not uncommon to have some USB devices working perfectly well (a Smartmedia card reader, a digital camera, an external CD-RW drive, etc.), yet a particular device (say a USB scanner) refuses to work from the motherboard no matter what action is taken.

Possible solutions

It could be that the troublesome device does not conform to the USB standards properly, or pushes the standards to their limits so that the device will work from some motherboards' USB ports but not from others.

Even after reflashing the BIOS and installing updates for the motherboard's chipset drivers,some motherboards' USB ports will not work with certain USB devices not matter what action you take short of buying a PCI USB adapter card (examples are shown at the end of this article). If you buy a USB 2.0 card, you will be able to use high-speed devices such as a CD writer or external hard disk drive.

You can also connect power-hungry devices, such as a scanner, through a self-powered USB hub (an example of which is also shown at the bottom of this page).

If you want to troubleshoot a particular USB problem not dealt with on this page, try using a search query such as: troubleshooting + usb + problems in a search engine.

You should be able to obtain the latest USB Controller and BIOS update from the computer's motherboard's site. If you can't identify the computer's motherboard from its user manual and you don't want to open the case to examine it, try use the free Belarc Advisor from or the free CPU-Z from

It is always a good idea to boot in Safe mode in order to clean out the Device Manager of repeat instances, which are not shown in Normal mode. (Press the F8 key at start-up to boot into Safe mode.) There should only be multiple instances of IRQ Holders for PCI Steering (if IRQ Steering is enabled in the Device Manager under System devices => PCI Bus in Windows 9.x). Otherwise there should only be one of every device showing. You should remove all of the instances so that Windows can reinstall only one. (Don't attempt this if you don't have a Windows CD, because Windows might ask for it.) If you leave one instance, Windows will add another instance, making two instances.

You should be able to find many articles that deal with such a cleanup by using a search query in a search engine, such as: clean + "device manager" + "safe mode" + "Windows 98".

You don't need to go into Safe Mode in Windows 2000 and XP to clean out the Device Manager, because there's an option in the View menu to Show Hidden Devices.

USB problems seem to be more common with VIA and SiS chipsets than with Intel chipsets. Microsoft has issued a patch for a USB problem in Windows 98 SE. The article is called "USB Devices May Not Work in Windows 98 Second Edition". Enter this reference number - 240075 - in the search box on this page:

The note says that it applies to VIA USB Controllers, but it can cure problems with SiS chipsets as well.

For motherboards with VIA chipsets, always install the VIA Hyperion or "Four-in-One" drivers from

A new USB 2.0 PCI adapter card cripples PC - an adapter card chipset and motherboard chipset incompatibility


A newly installed four-port USB 2.0 PCI card is preventing the computer from booting. There are no beeps from the BIOS and installing the card in different PCI slots makes no difference. Only the processor's fan works when the computer is started. There is nothing wrong with the PCI slots, because other cards work in them. A TMC A15VG+ Super Socket 7 motherboard is installed.

Possible solutions

The card itself could be faulty, but there are many reports on the Internet of cases in which USB cards using the VIA VT6202 chipset are causing older Socket 7 computers to lock up. The reports say that the USB cards work properly in other computers. The common factor is that the motherboards use the VIA MVP3 chipset, so is looks highly likely that there is a conflict between the VT6202 chipset on the card and the MVP3 chipset used by this TMC motherboard. If this is the case, updating the device drivers for both the card and motherboard might cure the problem, but the reports do not provide this as a solution, so, if doing that doesn't work, then either the motherboard must be replaced, or the USB 2.0 card must be replaced with one that does not use the VT6202 chipset.

The problem now is to make sure that the replacement USB card has a different chipset, because the one causing the problems is very commonly used. The Belkin F5U220 five-port USB PCI card and the Lindy 51074 card both use an NEC chipset. You should be able to locate local vendors by using a search engine, using the model names as the search query.

How things can go wrong with a USB device: an IRQ conflict


A SanDisk SDDR31 Imagemate USB card-reader works on a notebook computer running Windows XP, but when connected to a desktop PC running Windows 98 SE, a blue screen of death appears within 15 seconds of the device being connected to a USB hub, even though the software was loaded according to the instructions, followed by the installation of the latest device drivers from SanDisk.

The error message reads: "A fatal exception OE has occurred at 0028:c15b0527 in VXD APIX(01)+00003207."

Possible solutions

Any fatal exception OE that has a segment address of 0028 strongly suggests an interrupt request (IRQ) conflict, with it being most likely that the USB device is sharing an IRQ, and the device drivers are not properly programmed to enable IRQ sharing, which, of course, both Windows 98 SE and Windows XP support.

If you don't know anything about interrupt requests, and IRQ sharing, read this Q&A on this page: A new USB 2.0 adapter card makes my computer crash: a problem with IRQ sharing - or enter those terms as a search query in a search engine.

The first thing to do is in such a case is to check (or check again) for driver updates. If the latest drivers are loaded they should support IRQ sharing properly. If the problem still exists, the most likely cause is that an application has installed a conflicting version of the Apix.vxd file - the VXD file named in the error message.

Programs from Adaptec, Roxio Easy CD, and Direct CD are notorious for installing their own versions of the Apix.vxd file in the C:\Windows\System\IOSUBSYS folder. If any of these programs are installed on the system, upgrading them to the latest versions will allow you to restore the original Windows 98 versions of Apix.vxd and Wnaspl32.dll into this folder. This is because the latest versions of these programs don't share the Windows versions of these files - they place their own versions in their programs' folders.

The original Windows files should still be in the same folder and have been renamed with a .bak (backup) extension. If so, rename the existing Apix.vxd and Wnaspl32.dll to Apix.adp and Wnaspl32.adp, and then change the .bak extension on the backup files to .vxd and .dll respectively.

If the .bak versions of these files don't exist, then use the right mouse button to click on the Apix.vxd file, click Properties and check under the Version tab. If the Company name is listed as Adaptec instead of Microsoft, the Adaptec version of both of theses files have to be replaced with the Microsoft versions from the Windows 98 CD.

The easiest way to replace the files in a Windows 98 /98 SE system is to follow this path Start => Run - and enter sfc (to run the System File Checker). Choose the option that allows a single file to be extracted from the Windows CD, and enter the file's name in the search box. The source and destination folders do not have to be specified, because the SFC already knows them. Rebooting the system should solve the problem.

If there is still a problem, try conducting a Google Groups search by entering the the name of a newsgroup such as alt.windows98 in the first search box, followed by the error message (or part thereof) within double quotation marks in the second search box that comes up.

Note that the System File Checker still exists in Windows XP. But, for some reason, it has been well hidden. There is no information on it in Help and Support. It is run from the Command Prompt, which is opened by entering cmd in the Start => Run box. Enter the command sfc /? to bring up a list of the commands and switches that can be used with it.

It can be a useful problem-solving utility if you know how to avoid the pitfalls, which are provided on this page.

SFC Explained -

If you want to use SFC, you should have a certified Windows CD - not a System Recovery CD of the kind that comes with many brand-name computers instead of a Windows CD - because SFC makes use of it.

Why some USB devices work via a USB hub, while others will not


You computer has only two USB connections, so you buy a USB hub to connect more USB devices. For some reason, however, your USB devices, such as your Sandisk cardreader and your Microsoft Intellimouse, will not work on the hub. - You want to know why some USB devices work via a USB hub, while others will not. - And you need to know if there a solution to this situation.


First, you need to know if you are using a powered USB hub, which is itself plugged into an electrical outlet, or an unpowered hub that draws its power from the computer. USB cables have four pins; one for ground, two for data, and one for +5 volt power. If connected to the USB ports on the motherboard, your cardreader and mouse would both draw their power from the computer (through the USB bus), otherwise you would have to plug in a separate power adapter for each unit. It could be that those non-functioning devices are not receiving the proper amount of power through the USB hub. If it is a powered hub, then this probably is not the problem.

Another possibility is that your computer is not assigning each of the USB devices on the hub an identification address - a process called enumeration. This could be because of a bad or incompatible USB hub, or your machine might not be recognising the USB hub correctly. And if the USB hub came with software drivers, then you would need to install them to fix the problem.

You should try plugging a USB device, such as a printer that is powered from its own power adapter, into the hub. If the device works, then you know that it is a power issue with the other devices, and should contact the USB hub manufacturer. If that fails to solve the problem, return the hub, and try a different make and model, or try using the existing hub on another computer.

Problems with a powered USB hub

Jon Larsen - "I own a small computer shop and had a couple of powered USB hubs returned. I learned that some devices don't like being alone on a powered hub. Since learning this, I've told my customers to not power the hub unless devices don't work - in which case, they should power the hub. Haven't had a return since."

If the hot-plugging of a FireWire / USB device fails in Windows XP...

To hot-plug (hotplug) means plugging in the drive while the computer is running instead of when it is shut down.


You have a computer running Windows XP with a FireWire (IEEE 1394) adapter card installed Whenever you hot-plug a new external DVD-RW drive into one of the card's FireWire ports, it doesn't appear under My Computer. You have tried restarting the computer and reattaching the DVD-RW drive, but that has failed. You therefore want to know if there is remedy for the problem.


First, check that your FireWire adapter is installed and functioning properly. You can check the Device Manager by right-clicking My Computer and choosing Properties. On the Hardware tab, click Device Manager. If your FireWire Controller has an exclamation mark beside it, then you need to highlight the entry, remove it, and then reinstall its drivers.

If your IEEE 1394 FireWire card is installed and is functioning properly, you should know that Microsoft has recognised that this fault can occur when hot-plugging a FireWire or USB CD/DVD-ROM drive into a computer running Windows XP. Microsoft says that the fix for this is to install Windows XP Service Pack 1. Note you may require the same fix if you attach a digital video 1394 device that supports non-S100 data rates, and you see only a black window in Windows Movie Maker.

Problem: all of a sudden none of a computer's USB ports work

I have come across a case when someone asked me why all of a sudden none of the USB ports on his motherboard functioned on his Windows XP system. The first action I took was to have a look at the USB Controller entries in the Device Manager. They were there. I looked at what other devices were installed, and read through the motherboard's manual. I found out that the motherboard had a built-in AGP video card of one make, but also had an AGP video card installed of another make. I then rebooted the system and opened the Award BIOS setup program. Sure enough, the built-in video card was still enabled in the BIOS, so I disabled it. Having rebooted, the USB ports were working normally. The computer's owner had very recently installed a video card, but hadn't thought that disabling the motherboard's video chip was necessary.

Have I destroyed my motherboard, keyboard and wireless network adapter by using two USB ports at the same time that are linked together on the motherboard?


I repaired my desktop PC by replacing the motherboard with an ASRock P4VM890 Socket 478 motherboard for Intel Pentium 4 / Celeron D (Prescott, Northwood, Willamette) processors. It was working properly until I plugged a flash drive into one of the USB ports on the motherboard at the rear of the case. According to the motherboard manual, the port is shared with a USB port on the front panel of the case, which had a USB D-Link wireless network adapter plugged into it. The flash drive packed in along with the keyboard. I replaced the keyboard, which worked for a while but has now also packed in. The keyboard has a PS/2 five-pin DIN plug that is used with a USB adapter cable. The motherboard manual says that the two sockets will not function together, but it does not say that using both of them at the same time will cause damage.


The ASRock P4VM890 motherboard provides six USB ports from its ports panel that appears at the back of the case when the motherboard is installed in it. The motherboard also has two sets of headers on the motherboard itself for connecting USB ports in the front panel of the case with cables that are provided by the case.

This page on ASRock's site provides the manual as a download - If it doesn't work, you can try entering asrock p4vm890 in a search engine to find the current link.

The USB header at the bottom, near the SATA hard-disk-drive connectors and the third PCI slot, provides an additional two USB ports. The other header, located behind the USB ports on the motherboard's ports panel, shares a connection with two of them. You can't use both the front and back USB connections, which are connected to the same port, simultaneously. However, it doesn't seem likely that plugging in two devices would produce a short circuit, such as you describe, if the cable between the header and the front ports had been wired correctly.

Perhaps the front-panel connector cable from your case does not match the pin-out of these USB headers. There are several variations in the pin-out of USB headers. Most motherboard manufacturers, including ASRock, place the two 5V power pins next to each other, usually at the far end from the 'missing' pin of the nine-pin connector. However, some motherboard manufacturers reverse the order of pins on the second USB port, so one is arranged Power, Data-, Data+, Ground, and the other is Ground, Data+, Data-, Power.

Therefore, when you want to connect USB cables to a new motherboard, you should check the motherboard manual carefully. A multimeter set to DC volts can be used to check which pins are running at 5V. The wires in the cable are usually red when they are used to deliver power.

Read this illustrated article - How to Install Front USB by Connecting Front USB Ports to a Motherboard? -

Note that PS/2-to-USB adapters of the kind that you used to connect your PS/2 keyboard to a PS/2 keyboard USB port on the motherboard will only work if the PS/2 keyboard (or mouse) has been designed to work with both a USB and a PS/2 connection. You had that setup working, so they must be compatible.

It is more probably that the adapter has burnt out or been shorted by too much current. You could also find shorted leads in the front-panel USB cables. If you can, before using it again, use a multimeter set to resistance to check each possible combination of pins for a short circuit. It should be safe to use the keyboard in the motherboard's PS/2 keyboard port to find out if it is still working.

Unfortunately, the fourth and fifth USB ports could be permanently damaged. They are on the shared header and the right-most connectors, furthest away from the PS/2 keyboard port, on the back of the motherboard. A damaged USB port can damage other equipment permanently, so you should avoid using them.

Information on the most common FireWire (IEEE 1394) problems in the Microsoft Knowledge Base

If you don't find a problem that fits yours, click any article's Knowledge Base number and conduct your own search from that problem's page using its Search box by entering a suitable search query the describes the problem.

Click the MS Knowledge Base reference number to go to that article
Description of the problem
  The 50 most popular Knowledge Base articles -
Advanced troubleshooting tips for general USB problems in Windows XP -

Performance of 1394 [FireWire 800] devices may decrease after you install Windows XP Service Pack 2 - After you update your computer to Microsoft Windows XP Service Pack 2 (SP2), the performance of your 1394a or 1394b FireWire devices may be greatly decreased. A digital camera that uses S400 speed is an example of such a device. [A link is provided for a download that fixes the problem and information on how the Windows Registry must be edited is provided.]

When you use a USB-to-Serial converter to connect a device to a Windows XP-based computer, the data transfer from the computer to the device is slower than expected - This issue occurs because the Usbser.sys driver does not follow the USB specification. When the computer transfers data to a mobile device, the transfer process is based on the Usbser.sys driver. The Usbser.sys driver does not send zero-length packets when the total transfer size is an integer multiple of the packet size. However, zero-length packets are required by the USB specification so that the device can recognize when the packet transfer is finished.
Cumulative update rollup for USB core components in Windows Vista - This article describes an update rollup that resolves some reliability issues in the USB core components in Windows Vista. You will achieve better reliability in various scenarios by installing this update. [Numerous USB problems in Windows Vista systems are fixed by installing the update.]
Performance of 1394 devices may decrease after you install Windows XP Service Pack 2. - Provides an update to resolve the problem.
Some Devices Are Not Recognized When You Use Multiple IEEE 1394 FireWire Devices [Applies to Microsoft Windows XP Professional and Microsoft Windows XP Home Edition]
FireWire drives that are still connected to your computer may be unexpectedly removed in Windows after you unplug a separate drive. - Fixes a problem with the way that drives are enumerated after you remove one of several FireWire drives. [Applies to Microsoft Windows XP Professional and Microsoft Windows XP Home Edition]
Update for 1394 Storage Peripherals in Windows 98 Second Edition. - You may experience any of the following symptoms: Your computer stops responding (hangs) when you physically unplug a 1394 FireWire storage or peripheral device from your computer. You experience poor performance with your 1394 storage or peripheral device...
Network Browsing May Not Work Properly Over 1394 NDIS Network. - Windows ME - Client computers using Institute of Electrical and Electronics Engineers (IEEE) 1394 FireWire network cabling may not be able to use My Network Places to view other computers...
IEEE 1394 FireWire General Troubleshooting. - This article lists basic steps for troubleshooting Institute of Electrical and Electronics Engineering (IEEE) 1394 FireWire devices and host controllers. The following steps should assist in troubleshooting most problems with IEEE 1394 FireWire devices. [Applies to Microsoft Windows 2000 Professional Edition]
General Troubleshooting for IEEE 1394 FireWire Devices and Host Controllers. - This article lists basic steps for troubleshooting Institute of Electrical and Electronics Engineering (IEEE) 1394 devices and host controllers. The following symptoms and suggestions can help you troubleshoot most problems that concern IEEE 1394 FireWire... [Applies to Microsoft Windows XP Home Edition - Microsoft Windows XP Professional Edition - Microsoft Windows XP 64-Bit Edition]
An IEEE 1394 FireWire device drive may stop working when you turn on another IEEE device in Windows XP. - Describes how to work around a problem where an IEEE 1394 FireWire device stops working when you turn on another IEEE 1394 device in Windows XP.
Digital video camera is not detected correctly. - When you connect your digital video (DV) camera to your Microsoft Windows XP-based computer by using an Institute of Electrical and Electronics Engineering (IEEE) 1394 FireWire cable, you may experience one or more of the following symptoms... [Applies to Microsoft Windows XP Professional - Microsoft Windows XP Home Edition]
1394 FireWire Audio/Video Control Device Stops Working Unexpectedly. - After you play or record digital audio or video by using an Audio Video Control (AV/C) device, such as a 1394 AV/C hard disk or DV camcorder, the 1394 FireWire bus may stop functioning. The error message that is displayed by your media control software... [Applies to Microsoft Windows Millennium Edition - Microsoft Windows 98 Second Edition - Microsoft Windows 98 Standard Edition]
IEEE 1394 FireWire storage device detection does not work when the system resumes from standby or hibernation. - When an IEEE 1394 FireWire storage device, such as a CD-ROM or external disk drive, is connected to your Windows XP Service Pack 1 (SP1)-based system, the device-detection process may not work after the systems resumes from standby or hibernation....
Your IEEE 1394 FireWire or USB CD-ROM or DVD-ROM Drive May Not Be Recognized in Windows XP. - Under the following conditions, your IEEE 1394 or USB CD-ROM or DVD-ROM drive may not be recognized: You hot-plug your IEEE 1394 FireWire or USB CD-ROM or DVD-ROM drive. Your CD-ROM or DVD-ROM drive contains CD-ROM media when you connect it to your...
INFO: 1394 FireWire Device Not Being Detected. - Windows 98 / 98 SE - If a 1394 FireWire device is plugged into a 1394 FireWire host controller and Windows 98 fails to detect it, selecting the Support Non-Compliant Devices check box may correct this problem. After selecting the Support Non-Compliant Devices check box, the machine...
Stop Error Message in Cdr4_2K.sys When You Connect an iLink (FireWire) CD-RW DVD-ROM Combination Drive. - When you connect a Sony iLink CD-RW DVD-ROM IEEE 1394 FireWire combination drive to your computer, you may receive a "Stop" error message on a blue screen that is similar to the following: Stop: 0X0000001E (0xC0000005, 0xF7565A59, 0x00000000, 0x00000028)... [Applies to Microsoft Windows 2000 Professional SP4 - Microsoft Windows 2000 Service Pack 4]

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