Note that the BIOS can be write-protected. If that is the case (it is not usually necessary), before the BIOS can be updated, its write-protection has to be disabled by changing a jumper setting on the motherboard itself, or by changing a setting in the BIOS itself. If this needs to be done , the motherboard's user manual will provide the required information in the section devoted to the BIOS.

If it isn't broken, don't fix it

Note well that you should only reflash the BIOS for a specific purpose, such as to fix a known bug, or enable the use of a particular piece of hardware, because the flash process can go wrong. If it does in an irrecoverable way, your system will put completely out of action until you can get the BIOS program restored, or you purchase and install a new motherboard that has a functioning BIOS chip.

The manual reflashing procedure reprograms the BIOS chip on the motherboard, and is usually accomplished on a Windows 95/98/Me system by copying the flash utility and the new BIOS file to a floppy disk containing the three DOS system files that make it bootable.

Live BIOS updates, and running a utility included in the BIOS itself that updates it

Some motherboard manufacturers such as MSI, have an application that locates, downloads, and updates the BIOS automatically. MSI's application is called MSI Live Monitor, which can also update the motherboard's drivers and graphics drivers if the motherboard has an integrated graphics chip.

You can install the application from the CD that came with your MSI motherboard, or access it via the company's site. It is an automatic procedure that downloads an executable BIOS update to your hard disk drive, then reboots the computer and runs the executable file, which is programmed to perform the update.

You install MSI Live Monitor. When it is installed, the MSI Live Monitor icon appears on the Desktop. You double-click it to run the application. The Live BIOS and Live Driver tools locate the latest BIOS, driver, and firmware files. If you select them to be updated, they are then installed automatically. The Live Update application can be scheduled to look for updates on MSI's website.

Some MSI motherboards also have a BIOS update feature that operates from the BIOS itself. No bootable floppy disk with the BIOS files on it is necessary. You just download the update file and enter the path to it in the utility. This has been provided now because Windows 2000 and Windows XP do not have a DOS mode. You obviously cannot access the Internet from the BIOS, because you have to have Windows up and running to do so.

I updated my MSI 7093 motherboard's BIOS by using the Live Update feature without any problem. You are informed that you are using it at your own risk and you are advised to create a back-up floppy disk the copies the old BIOS to the floppy disk and creates a boot disk that restores the old BIOS automatically if you boot the system with the boot disk. You would only do that if the update procedure fails and you can't start up the system. It is very advisable to create the boot disk, because if there is any kind of failure the BIOS update will go wrong and render the PC unbootable.

Most of the motherboard manufacturer's still provide the option to create a boot disk that reflashes the BIOS at system startup when the boot floppy disk (that contains the system boot files, the utility that updates the BIOS, and the updated BIOS file) is placed in the A: drive. Apart from running the update utility in Safe mode, using a boot disk used to be the only way to update the BIOS, but, as I said, using a live BIOS update works very well as long as you follow the instructions and disable monitoring software, such as a virus scanner, and close all running programs before you run it.

Note that most motherboards now allow the user to restore a corrupt BIOS file from a USB flash drive that contains a backup or downloaded BIOS file.

You should read your computer's motherboard manual to find out how BIOS updates are installed. If you don't have a copy, download one form its motherboard manufacturer's website. If you need a quick way to identify a PC's processor, motherboard, and RAM, the free CPU-Z is ideal. It provides plenty of information on those components in Windows 95/98/Me/XP/Vista. When you know the make and model of the motherboard, you can locate its manufacturer's site by entering that information into a search engine (such as the Google search box provided at the top of this page (with its Web radio button enabled).

Replacing the BIOS file from a bootable CD

Some new motherboards, such as those made by Asus, provide the BIOS files on a bootable CD. The following is an extract from the user manual for the Asus A8N-E Socket 939 motherboard for AMD Athlon 64 processors.

Asus CrashFree BIOS that restores the BIOS from a bootable CD

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The PC starts up showing a company logo instead of the memory count

Note that MSI BIOSes have a setting in them that produces the MSI start-up screen instead of the usual memory count and system information screens. You have to enter the BIOS and disable the setting to make the memory-count screen appear at startup. Here is the description of the setting in an MSI motherboard manual:

"Full Screen LOGO Display - This item enables you to show the company logo on the bootup screen. Settings are: [Enabled] Shows a still image (logo) on the full screen at boot. [Disabled] Shows the POST messages at boot."

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Note that in Windows Me, 2000, XP and Vista, the BIOS can also be reflashed by using a utility within the BIOS itself, because the DOS functions in Windows Me has been cut back, and has never existed in any of the versions of Windows 2000 and Windows XP. The two Award BIOS start-up screens shown at the beginning of this article show the instructions on how to open the BIOS itself and how to run the built-in flash utility. With the BIOS installed in the system running the Pentium 4 2800MHz processor these words are shown at the bottom of the start-up screen - "Press DEL to enter SETUP, ALT-F2 to enter EZ flash utility."

However, in spite of this new inbuilt ability in the latest BIOSes, most motherboard manufacturers are still recommending creating a DOS boot floppy disk in order to flash update a BIOS in Windows Me, 2000, and XP systems.

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The three DOS files are command.com, io.sys, and msdos.sys, which can be transferred to the floppy disk by typing the command sys a: in at the C:\> prompt.

You can also create a boot floppy disk that has the three MS DOS files required to flash a BIOS by formatting it with the command format /s entered at the A:\> prompt. You can then use your zip/unzip program to extract the new BIOS file and the utility that does the reflashing to it, so that the boot disk now has only five files on it.

If the drvspace.bin (the DriveSpace file compression utility) file is copied to the floppy disk, remove it, because it will use memory required by the flashing process when it is loaded from the floppy disk into the maximum of 640KB of conventional memory.

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Often, the latest (software) device drivers, and the latest BIOS, are required to be installed in order to be able to run new hardware, and hence the software that it is designed to use.

Other new hardware and software, such as a new motherboard, operating system upgrade, or software patch from Microsoft, might also be required.

For instance, you will not be able to run an Ultra ATA/33 or ATA/66 hard disk drive (HDD) at the 33MB or 66MB data transfer rates (respectively) unless you have an operating system (Windows, FreeBSD, Linux, Unix, etc.), a motherboard, and a BIOS that supports them.

Fortunately, all ATA IDE hard disk drives are backward compatible.

This means that if the correct BIOS file is installed, you should be able to run ATA/66, ATA/100, ATA/133 drives on a motherboard that was designed to run earlier types, such as ATA 1, ATA 2, and ATA/33 drives.

That is, the new drive will merely use the highest supported data transfer rate. So, if ATA/33 is the highest data transfer rate supported by the operating system, the BIOS, and the motherboard chipset, that is that rate that an ATA/66 drive will use.

However, some ATA/33 or /66 drives require a software fix that makes them run in earlier data transfer modes, so it is advisable to check the manufacturer's website for all of the relevant information before you purchase a new drive for installation on an ageing motherboard.

Seagate's website has good FAQ pages on hard disk drives and their installation.

All of the major hard disk drive manufacturers provide software that makes installing a new HDD easy.

There is also a great deal of information to be obtained on IDE and SCSI hard disk drives on the IDE and Technical Stuff pages of this site.

The safest way to upgrade RAM: Use the UK and US Crucial Memory Advisors

Paul Mullen, the highly-respected computer guru of the Helpfile at ComputerShopper.co.uk - "I have recently been buying my memory only from Crucial Technology. I would rather pay the extra cost than waste time trying to track down the obscure program faults that bad memory can cause."

The memory requirements of the versions of Windows Vista

Most of the versions of Windows Vista require more RAM memory to run optimally on a computer that doesn't use memory-hungry applications than Windows XP. A video-editing application is an example of memory-intensive software. Only Windows Vista Home Basic has a recommended minimum amount of memory of 512MB, which is the same amount recommended for Windows XP. Windows Vista Home Premium, the most popular version and Windows Vista Ultimate require a recommended minimum of 1GB (1024MB) of memory, which is twice the amount of minimum memory recommended to run Windows XP. Read the information on the RAM pages of this site to find out if you should buy memory for use in single-channel or dual-channel modes.

UK - Crucial Memory Advisor - UK

USA - Crucial Memory Advisor - USA

For example, if your computer has an Asus motherboard, open the menu, scroll down to ASUS, and click GO. If, say, you have a Dell computer, scroll down to DELL, and do likewise. You will be taken to the relevant information on Crucial's website.

If you don't know the make and model of the motherboard installed in your computer, here is a good free utility - Belarc Advisor - that creates an analysis of the hardware and software on a personal computer. Look under FREE DOWNLOAD - http://www.belarc.com/. Another utility that also provides detailed information on the memory itself is CPU-Z.

The processor's BIOS settings and monitoring capacities

If you have read the Motherboard pages on this site, you will know that the settings for the processor front side bus frequency (FSB), clock-multiplier, and voltages, can be set by setting jumpers or DIP Switches that are on the motherboard, or by using the BIOS setup program.

Shown below are the processor BIOS settings for the Abit AT7 motherboard - available for both the AMD Athlon and Intel Pentium 4 platforms - which uses the BIOS (instead of motherboard jumpers or DIP switches) for all of the processor's settings. This is the easiest way to set a motherboard, and Abit are past masters at providing the means to do it this way. This motherboard is an overclocker's dream because of the wide range and scope of its SoftMenu BIOS settings.

Processor BIOS settings

The BIOS can also be used to monitor the system. BIOS settings are capable of monitoring the processor's temperature, fan speed, and voltages. Some BIOSes allow you to set a temperature that sets off an alarm or shuts the system down if it is exceeded.

With the Athlon 64 processors, AMD allows the free choice of clock multiplier settings for the purpose of overclocking - even though the processor itself can only tolerate a few hundred megahertz of extra speed - and then only if the motherboard supports alternative clock-multiplier settings. See the relevant BIOS page (below) for the clock-multiplier settings on a motherboard with an Athlon 64 processor installed.

The clock multiplier settings in the BIOS of a motherboard running an Athlon 64 FX-51 processor

The X stands for the motherboard's FSB setting, which in this case is 200MHz. AMD uses a Pentium Rating (PR) method to rate its processors, so the 16X clock-multiplier setting (or CPU RATIO) represents 16 multiplied by the FSB of 200MHz, giving the processor a PR of 3200+ - the intended setting for this processor, which should display as such on the boot screen instead of its clock speed/frequency of 2200MHz.

If a 17X clock-multiplier setting were available, the processor would be running at an overclocked PR of 3400+, etc.

For more information, click here! to go to the page that deals with overclocking on this site.

How to get rid of a PC's brand-name logo or motherboard logo in order to view the POST information

If the system starts up showing a manufacturer's logo instead of the Power-On-Self-Test (POST) information, such as the audible beep issued by the speaker in the PC's case, the memory count, and the tabled information on the hardware, it is generated from the BIOS setup program, not from software that is set to load at startup. The manufacturer's logo could be that of the PC's manufacturer, such as Dell, HP, Gateway, etc., or the manufacturer of the motherboard, such as MSI, Asus, Abit, etc., or even the developer of the BIOS itself, such as Phoenix or AMI.

It is worthwhile seeing the POST screens because unexpected changes in the startup information could indicate a problem with the RAM memory, or indicated that a hard disk drive or CD/DVD drive has not been recognised, etc.

Some BIOS setup programs allow the logo to be temporarily disabled so that you can see the startup information by, for example, pressing the Tab or Esc key during startup. Other BIOSes have an internal setting that enables or disables the logo. Not all BIOSes have the option to disable the logo, but if yours does, the BIOS page that the setting is on has a title such as Advanced BIOS Features, which is the case in a Phoenix BIOS. In the Phoenix BIOS of an MSI motherboard used by the PC I am working on now, the setting has this name: Full Screen Logo Show. Enabling it shows the MSI logo at startup; disabling it shows the POST information.

How the BIOS can make a difference

A good example of how the BIOS can make a vital difference is the case of AMD K6-2 and K6-3 processors.

The K6-2 450MHz processor and the K6-3 range of processors use a new CXT core that requires a BIOS upgrade in order to function on motherboards designed to use the previous processor core. Without this BIOS upgrade, these processors will not function, even though the motherboard can run K6-2 266MHz to 400MHz processors.

Most computer manufacturers (Dell, HP, Compaq, etc.) and motherboard manufacturers (Asus, Abit, FIC, etc.) install flash BIOS chips on their motherboards, which can be upgraded from a floppy disk by using a utility downloaded from their websites instead of replacing the BIOS manufacturer's chip on the motherboard.

The problem is, many firms that have their motherboards manufactured cheaply in the Far East do not provide flash BIOS upgrades for their motherboards, either from their websites, or through the post. So, before you make a purchase, make sure that you can obtain BIOS upgrades and the latest device drivers, either from the vendor, the manufacturer of the computer, or from the manufacturer of the BIOS chip.

When a new piece of hardware, such as a new type of HDD, or video card, is introduced, the software driver for it is often far from being honed to perfection. Therefore, the opportunity to download the latest drivers for devices from the major manufacturers and/or vendors usually exists.

Most reputable motherboard manufacturers have websites from which BIOS and IDE driver upgrades can be obtained.

Note that it is always essential to obtain flash BIOS file upgrades from the computer's manufacturer (Dell, HP, Compaq, etc.), or the computer's motherboard's manufacturer, (downloaded from their websites), because the original BIOS was probably customised for that particular motherboard.

The motherboard manufacturer can add or remove BIOS settings to suit its needs. If, say, it discovers that BIOS settings are creating support issues, it will remove the ability to enable or disable the offending settings, and make the BIOS set them automatically.

Loading an uncustomised flash upgrade obtained directly from a BIOS manufacturer such as Award would overwrite the original BIOS and may render the computer inoperable if the original BIOS cannot be restored, having not been saved to a floppy disk by using the same utility that reflashes the BIOS.

BIOS recovery services

An inexpensive BIOS recovery service, among other BIOS related matters, is offered at the following websites - The Flashbios Site - BIOS Wizard - and BadFlash.com.

Apparently you can send your BIOS chip in to these businesses to have it reprogrammed to order in those cases where the BIOS file has become corrupt and cannot be reflashed.

You can also try entering a term such as bios + recovery, as is, in the Google search box provided at the top of this page (with its Web radio button enabled). The power of these search engines is astonishing. You could probably spend all day looking at all of the BIOS-related links that Google can find.

The actual process of flashing a BIOS file

Although Windows 2000, Windows XP and Windows Vista do not have MS DOS, and Windows Me only has limited MS DOS functionality, the motherboard manufacturer's are still providing information on how to reflash the BIOS with an MS DOS boot floppy disk. Here is a page on the Gigabyte site that provides information on all three available methods:

How to reflash Motherboard BIOS -

http://www.gigabyte.com.tw/Support/Motherboard/HowToReflashBIOS.aspx

Note that you can adapt any boot disk used with the last versions of MS DOS (5.x and 6.x) or Windows 9.x, and use it to reflash a BIOS chip in a system running Windows Me and Windows XP. The files system in use - FAT or NTFS - is irrelevant, because the boot disk is not being used to install the operating system. The procedure to adapt a boot disk so that it is suitable for reflashing a BIOS chip is given below.

Visit http://www.bootdisk.com for a Windows Me boot disk.

Click here! to go directly to the BIOS-related links on the first of the four Links pages on this site.

Doing a Google Groups search using the search phrase flash + bios (as is), should produce many pages of links to threads of past Usenet newsgroup postings.

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A BIOS file update is usually downloaded as a zip file, or as a self-extracting .exe file that can be extracted to a boot floppy disk, or folder on a PC's hard disk drive by using WinZip or any of a number of free zip-file programs (to find them enter a search term such as free + zip + file + program in the Google search box at the top of this page, with its Web radio button enabled). An example is ZipGenius.

Note that Windows XP and Windows Vista can open and extract zip files natively when you click on the .zip file. However, depending on how recently updated your PC is, you may experience a long extraction time. Read the following forum thread if you do:

.zip files will not extract in Vista Business OS -

http://forums.microsoft.com/Communities/ShowPost.aspx?PostID=1150192&SiteID=6

Before reflashing a new version of a BIOS file into your computer's BIOS chip, read the instructions very carefully.

A BIOS file is usually flashed (installed) from a floppy disk because a clean boot is required to avoid the memory management software (himem.sys and emm386.exe used in Windows 9x systems) that is installed when the computer boots to the hard disk drive. Those files are not used in Windows 2000/XP/Vista, which is why it is easy to use a live BIOS update with those versions of Windows and why that method can't be used with the Windows 9x versions of Windows.

The new BIOS must have been specifically designed for the particular model of motherboard by the motherboard's manufacturer, not the BIOS manufacturer.

Flashing a general BIOS downloaded from Award.com could render your computer inoperable, because the BIOS file is customised by the motherboard manufacturer for each make/model of motherboard. In short, the correct BIOS file for a particular make/model of motherboard has to be used.

New BIOS files enable new hardware to be used, and rectify software bugs between the BIOS and Windows.

You should back up the BIOS before reflashing it. It is also a good idea to make a backup copy in case the BIOS becomes corrupt. Read this page on how to back up the BIOS:

BIOS Backup - http://www.hardwaresecrets.com/article/41

Note that some motherboards have two BIOS chips - a main chip and a backup chip. If the main BIOS is corrupted accidentally by an unsuccessful BIOS upgrade, or by a virus, the motherboard uses the backup BIOS chip automatically. The motherboard's user manual should tell you if your PC's motherboard has dual BIOS chips.

You can usually download a motherboard user manual from its manufacturer's site if you know the make/model of the motherboard. If you don't have that information, the free CPU-Z utility can provide it. You can then locate the manufacturer's site by making use of a search engine, such as Google.

If you don't have a backup and you have to enter the BIOS to restore the settings to what they were before a system failure wiped them out, you can do it manually if you know what the settings are, or you have a record of them.

If you have to enter the BIOS to restore the settings to what they were before a system failure wiped them out, you can do it manually if you know what the settings are, or you have a record of them.

The motherboard's manual should provide a section that explains the BIOS settings and what the fail-safe and/or default settings are.

If you don't have a record of the settings, or don't know from having set them what they were, there is usually a setting in the BIOS called Load Setup Defaults. These are the settings that were set by the computer's manufacturer. They probably won't be the optimal settings, but they will allow the system to function properly.

In AMI BIOSes, there is usually a setting called Auto Configuration with Optimal Settings that can be used to restore the BIOS settings. Again, in spite of the name, these settings probably won't be the best ones, but they will be good enough to get the system up and running.

Some information you might not be able to find out about Award BIOSes is as follows.

Before reflashing the BIOS, enter the BIOS Setup program and click the LOAD BIOS DEFAULTS option. This loads the minimal BIOS settings. AMI BIOSes will have a menu item called something like Auto Configuration with Fail Safe Settings. The terms used vary between BIOS manufacturers.

Scroll to SAVE & EXIT SETUP. In the window asking if you want to SAVE TO CMOS AND EXIT (Y/N)? N - change the flashing N to Y and press the Enter key.

This is done because there may be advanced BIOS settings that can prevent the flash process from taking place.

Select SAVE & EXIT SETUP as before.

If you have a Windows 95/98/Me system (Windows 9x) and you booted from the floppy disk containing the three MS DOS system files, the new BIOS file, its installation utility, and you can get no further than the message Insufficient Memory! this is probably because the process can only use the 640KB of conventional memory that is used in Windows 9x systems (not in Windows 2000, XP, and Vista).

To reduce the memory used by these files, transfer the system files to the floppy disk, as per instructions, from a computer running MS DOS versions 6.0 to 6.22, and then make sure that the hidden system file drvspace.bin is deleted from the floppy disk. This is a file-compression utility that should not be loaded automatically into conventional memory from the floppy disk. Windows 95/98 contains version 7.x of DOS, the system files of which are much larger than those of versions 6.0 to 6.22 so the earlier versions will use less conventional memory.

Note that you can only delete hidden system files if the Hidden, Read-only, and System file attributes are removed, either from within Windows (click Help and enter attributes in the Index dialog box) - or at the DOS prompt. At the DOS prompt enter attrib /? for the relevant switches.

Remember, to complete the start-up floppy disk, by typing the command sys a: in at the C:\> prompt, the three MS DOS 6.x or 7.x system files are copied to it (COMMAND.COM, IO.SYS, and MSDOS.SYS), and then you add the correct BIOS flash utility, and the new BIOS file that you want flashed into the BIOS chip.

These five files on a floppy disk are the only ones necessary to flash the new BIOS file into the BIOS chip on the motherboard.

Remember to follow the instructions to flash a BIOS file exactly. The instructions are usually provided either on a read-me file that comes with the BIOS files, on the motherboard's website, or in the motherboard's manual.

The commands that you enter at the DOS prompt vary from BIOS to BIOS, so I am not giving a set of commands here.

BIOS Recovery

AMI makes use of a Boot Block area of the BIOS to recover the system in the event of a corruption of the BIOS. Award uses a similar recovery procedure to AMI. This page provides information on the recovery procedures used by both of those major BIOS developers.

BIOS Recovery - http://www.biosman.com/biosrecovery.html

Using Safe mode to reflash a BIOS file

Note well - you should only reflash the BIOS for a specific purpose, such as to fix a known bug, or enable the use of a particular piece of hardware, because the flash process can go wrong. If it does, your system will put completely out of action until you can get the BIOS restored, or you purchase and install a new motherboard that has a functioning BIOS chip.

The usual method given to reflash a BIOS involves creating a boot disk containing only three MS DOS files, the file of the flash utility that does the reflashing, and the file containing the new BIOS information. You use the boot disk to boot the system and then enter a specific set of command instructions in at the A:\> prompt.

However, as I said above, this procedure often does not work because you get an Insufficient Memory! message, or perhaps the system fails to boot. Therefore, I do not use the boot-disk method myself. There is a quicker, more reliable method.

This involves copying the flash utility file, and the BIOS file (say, flash73.exe and je439.bin) to the root directory of the drive (usually C:\), and then restarting the system so that it boots to the Safe mode command prompt, which is itself done by pressing the F8 key just before your version of Windows loads. You can then enter the command line (provided in the reflashing instructions in a readme file that is contained in the zip file containing the other files) that loads the BIOS flash utility, which then reflashes the BIOS chip with the new BIOS file.

Make sure that you choose the Safe mode command prompt from the boot options, and not just the ordinary command prompt, because the flash process needs to avoid the memory managers that are loaded at boot up. That is why a boot disk is usually used. But these memory managers are not loaded to bring up the Safe Mode Command Prompt, so it is as safe a way to reflash a BIOS as any other. I have used this method myself on several occasions without any problems.

BIOS websites

Note that if you want information about a particular BIOS setting, you should be able to find it by entering an appropriate search term in a Google search box provided at the top of this page (with its Web radio button enabled). For example, to find out about the Reset Configuration Data BIOS setting, enter bios + setting + "reset configuration data", as is, in the search box.

Bioscentral.com -"BIOS Central is not for everyone. It is intended to be a technical reference home site for technicians and advanced computer users who troubleshoot computers using Power-On Self-Test cards or diagnostics, developers or technicians who want to find or add POST code information, users who want to flash their BIOSes, people who want to solve computer hardware or firmware problems, and anyone who wants to submit or read a competent review on PC maintenance products like diagnostic software, test cards, and recovery tools and other utilities. You are still welcome if you are a computer neophyte. On both sides of this text you can see many links to click on to access our reference lists and other material. You may learn some useful and interesting things here." - http://www.bioscentral.com/

BIOS from A to Z -

"Turn on hidden power functions, boot faster, speed up RAM and your CPU, tune your chipsets, deactivate unused functions... Secret BIOS settings can make Windows XP better, faster, and more stable."

Remember that it is possible to set a combination of BIOS settings that render a computer completely unbootable. That means that you won't even be able to enter the BIOS itself. Therefore, before you experiment with the settings, find out how to reset the BIOS with the default settings. Click here! to go to the information on how to do that on Page 1 of this article. Also remember not to change more than one setting at a time so that you know which setting is the cause of a problem. -

http://www.tomshardware.com/2006/01/04/bios_from_a_to_z/index.html

The following hyperlink takes you to probably the best BIOS information site on the Internet that also provides useful links to other BIOS sites. -

Wim's BIOS Page - http://www.wimsbios.com/

Basic BIOS Tweaking Guide (12/07/2001) -

http://www.tweaktown.com/document.php?dType=review&dId=67

BIOS Tuning Guide (26/02/2002) -

http://www.tweaktown.com/document.php?dType=review&dId=192

BIOS Tweak and Settings Guide -

http://www.3dspotlight.com/tweaks/bios/print.shtml

LostCircuits BIOS Guide - http://www.lostcircuits.com/advice/bios2/1.shtml

BIOS (CMOS) Battery Replacement Site - How to replace a BIOS battery -

http://www.monster-hardware.com/modules.php?name=Content&pa=showpage&pid=6

For a BIOS tweaking utility visit the TweakBIOS site.

If you want to know the technical details of how the BIOS works, visit this article. -

How the BIOS Works - http://computer.howstuffworks.com/bios.htm

Click here! to go to Page 1 of this article

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