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How Microsoft Product Activation (WPA) Works in Windows XP, Windows Vista and Windows 7 & 8, Including Problems and Solutions

Windows Product Activation (WPA) is part of Microsoft Product Activation (MPA) that is a feature of several Microsoft products, including every version of Windows from Windows XP to Windows 10 and MS Office.

WPA is the feature in Windows XP Home and Professional Editions (and all of the versions of Windows Vista, Windows 7, Windows 8.1 and Windows 10 for home use) that has to be activated within 30 days (in the retail copies) if the computers with those versions of Windows installed on them are going to be able to continue using them. Product Activation in Windows Vista and Windows 7 and 8/8.1 is very similar to what it is in Windows XP.

Due to the fact that Windows 10 is a free upgrade for a year after its official launch (from 29 July 2015 to 28 July 2016), Product Activation has changed for Windows 10 Home and Pro editions. Depending on how Win10 was obtained, activation is executed by a process called "digital entitlement" that does not require a Product Key or by using a 25-digit Product Key.

Here is the page on Microsoft's site that provides the details:

Activation in Windows 10 -

Windows 10 Product Activation

There is a new method of applying Product Activation in Windows 10 called "digital entitlement" that does not require using a Product Key. There are several circumstances in which it is applied, the main one being if Win10 was obtained by upgrading Windows 7 and 8.1 to Win10 online - a free upgrade until July 28, 2016 - but there are circumstances that still require the use of a Product Key.

The following page on Microsoft's website provides all of the options that require the new method of activation or that still use the previous method.

Activation in Windows 10 -

The following note appears on that page:

"Note: Starting with the November update, Windows 10 (Version 1511) can be activated using some Windows 7, Windows 8, and Windows 8.1 product keys. For more info, see the section Activating Windows 10 (Version 1511 or higher) using a Windows 7, Windows 8, or Windows 8.1 product key in this topic."

Windows 8 Product Activation

When Windows 8 is installed and connected to the web, it connects to a Microsoft server and activates automatically. The end-user licensing agreement, or EULA, for Windows 8 Pro states: "If the licensed computer is connected to the Internet, the software will automatically connect to Microsoft for activation."

New PCs, which have OEM licences that can only be used on the PC it was preinstalled on (a retail licence can be installed on as many PCs as the user wants to install it on as long as only one of them is in use), come with Windows pre-activated at the factory, so the Product Key is only needed and activation is only witnessed by the users who upgrade to Windows 8 from an older version of Windows or perform a clean installation and by system builders who buy an OEM licence in order to install Windows 8 on a custom-built PC.

Windows 8 moves to BIOS-based product keys -

"Product keys for Windows 8 computers aren't printed on a sticker. They're encrypted in the BIOS. How might that affect you?" - This means that when you perform a clean installation of Windows 8 on a brand-name desktop or laptop computer that came with Win8 preinstalled, you won't be asked to enter the Product Key during the setup process, as is the case with previous versions of Windows since XP. Note, however, that you do get a Product Key when you buy Windows 8 as a download or DVD, otherwise you wouldn't be able to install it.

It you experience any problems with activation, the following webpage suggests solutions: Why can't I activate Windows? -

Windows 7 Product Activation

During the installation of Windows 7, the option to activate it automatically when online is presented as the default setting. You just have to remove the check mark in the box beside that option so that you can choose when to activate. You have 30 days before you have to enter an activation key, but this can be extended to 120 days. The following article provides the information on how that can be done.

To find out how many days you have left, click Start => right-click Computer, and choose Properties. At the bottom of the window that comes up, you should see this heading: Windows Activation. It will say: "Windows is activated" and provide the Product ID or provide the number of days remaining of a trial period.

Use any version of Windows 7 free for 120 days -

Product Activation failed when a user tried to use Anytime Upgrade incorrectly to upgrade from Windows 7 Home Premium to Windows 7 Professional

The following Windows 7 Product Activation problem (translated by me) was answered on a computer forum:

"My wife bought a new Toshiba laptop for me which had the basic Windows 7 Home Premium and with it was another disc for Windows 7 Professional. After a while she wanted the professional version installed. I went to the Control Panel and went to Windows Anytime Upgrade and all I had to do was enter the Product Key and everything was okay until today when I keep being asked for activation and to enter the key again, which I have done but unsuccessfully. Can anyone tell me what I am doing wrong please?" -,93865.0.html

Installed a Windows 7 Upgrade version but its Product Key doesn't work

Otherwise, Product Activation is much the same as it is for Windows XP and Windows Vista.

If you installed a Windows 7 Upgrade version and its Product Key doesn't work, Microsoft recommends calling the company to validate your copy of Windows 7 over the telephone - something that is usually quick and painless. Just remember that to qualify to use an Upgrade version, you must be running a genuine, qualifying copy of Windows XP or Windows Vista. Earlier versions (Windows 98, Me, 2000, etc., do not qualify.)

The relevant clause in the Windows 7 licence agreement (the EULA) says: "To use upgrade software, you must first be licensed for the software that is eligible for the upgrade. Upon upgrade, this agreement takes the place of the agreement for the software you upgraded from. After you upgrade, you may no longer use the software you upgraded from."

This means that although it is technically possible to install an Upgrade version of Win7 to an empty partition on a hard drive or a new hard drive without overwriting the version of Windows that is being upgraded, it is not legal to do so. Which, in turn means that you cannot create a dual-boot system using the version of Windows that qualified you to make use of the Upgrade version. If you want a legitimate dual-boot system with your existing installation of Windows XP, you have to buy the full version of the version of Win7 that you want to install.

If your computer qualifies, but you can't get the Product Key to work, get the information ready that is required to verify that you qualify and then call Microsoft. The easy way to get Microsoft's Windows 7 activation telephone number is to click Start and enter slui 4 in the Search programs and files box and then press Enter.

However it is possible to activate with an upgrade Product Key without calling Microsoft at all. For example, Paul Thurrott shows how you can activate a Windows 7 Upgrade installation if it failed to do so by using a Registry hack. Read Method #2: Registry hack on this page:

A much lengthier method is to install from the Windows 7 Upgrade disc and then upgrade Windows 7 on top of itself - a method that also works for Windows Vista. For the second installation, follow the instructions to upgrade, but choose the Upgrade instead of the Custom option, because you're upgrading to Windows 7 from Windows 7. Enter the Product Key when requested to and Win7 should be validated and activated the next time you're online.

I installed the Upgrade version of Windows 7 to a new hard disk drive on my desktop PC. Why has Product Activation failed?

Click here! to go to the Q&A that deals with this problem on this website.

That said, the corporate version of Windows XP Professional (used by companies) doesn't require to be activated. MS Office XP, Office 2003, and Office 2007 require activation before the package is used 5 to 50 times, depending on the version.

If a computer is not connected to the Internet, the product can be activated by dialling the telephone number provided for the user's country.

If activation has not been completed within the trial period, Microsoft products shut down some of their features temporarily. MS Office loses the ability to edit and save files. After the activation deadline for Windows Vista runs out, the user can only use Internet Explorer to activate the operating system or buy a new license.

Note that you will only have to activate Windows XP/Windows Vista/Windows 7 if you purchased and OEM or retail copy and installed it yourself. If you have purchased a brand-name PC with Windows pre-installed, it will already have been activated.

Windows 7 installs with the default setting that it will activate as soon as the computer goes online. However, should you wish to choose when to activate, you can disable that setting during the installation by removing the check mark in the box beside the option.

You should not confuse Product Activation and registration. Product Activation is required, but registration is not compulsory. Registration involves signing up for product support and other product benefits.

Microsoft's licence (embodied in the EULA or End User Licence Agreement) that covers the legal use of Windows XP and Windows Vista limits it to being installed on only a single computer, which excludes having the same copy installed on a laptop/notebook computer as well as a desktop computer. Only MS Office is licensed to be used on both a notebook and a desktop PC.

Note that the Microsoft Office Home and Student 2007 version of MS Office was the first version to come with three licences, which means that it can be installed and activated on three computers. Now the Windows 7 Home Premium edition comes in a Family Pack that provides three licences. If one of those computers is no longer in use, its licence can be used on another working computer, because the Family Pack provides the retail version that can be installed on as many working computers as it has licences. Only an OEM version of Windows can only be installed on the computer it was originally installed on. If that computer becomes useless the licence cannot be passed on to another computer.

After activating Windows Home and Professional Editions of Windows XP ten times, for whatever reason, you have to activate them over the telephone. Apparently, this will no longer be the case with Product Activation in Windows Vista.

To activate Windows Vista when you are online, just enter activation in the Search box of Start => Help and Support. This is the information that comes up:

Activate Windows on this computer

You must activate Windows within 30 days after installation or Windows will stop working. Activation helps verify that your copy of Windows is genuine and that it has not been used on more computers than the Microsoft Software License Terms allow. In this way, activation helps prevent software counterfeiting. With an activated copy of Windows, you'll be able to use every Windows feature.

Click to open Windows activation. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

You just have to click where indicated by the link on Click to open Windows activation to activate Vista. The process takes a few seconds on a broadband connection, and not much longer on a dial-up connection. You will receive confirmation that Vista has been activated.

Installing many device-driver updates can trigger a request for reactivation in Windows Vista

It is not advisable to update every device driver in Windows Vista. According to reports on the web, some driver updates require the reactivation of Vista.

Note that installing many third-party device driver updates can trigger a request for activation. WPA does not care where the drivers come from, so, to avoid problems, you should obtain third-party device driver updates directly from the hardware manufacturers instead of via Windows Update and you should avoid installing too many at once. Several new third-party drivers installed at once, from any source, can make Windows require reactivation. Windows contains many internal device drivers of its own. Some Windows updates and service packs contain updates of these necessary internal drivers. Unfortunately, these can also make Windows Vista demand reactivation.

Windows Vista activation problem: Some users of Windows Vista report repeat activation requests


I have a valid copy of Windows Vista Home Premium and I have activated it, but now and then it asks me to activate it again, and when I do it says that I must do it by phone. However, when I reboot my PC, it shows as activated. There are no problems, everything still works, but I would like to stop this from happening.


There are several reports from Vista users on the web of this happening. Repeat Vista Activation Request -

Perhaps the information in this article will provide a fix for the problem:

Microsoft allows bypass of Vista activation - "Microsoft always says it opposes "software pirates" who sell thousands of unauthorized copies of Windows. But the Redmond company has made things a lot easier for pirates by adding a line to the Registry that can be changed from 0 to 1 to postpone the need to "activate" Vista indefinitely." -

Note that there are special considerations if a copy of Windows XP has an OEM (Original Equipment Manufacturer) licence (US: license), which is provided by the manufacturer of the computer that it is installed on. More information on an OEM licence is provided further down this page.

Many people have been led to believe that WPA contacts Microsoft on a daily basis to inform the company what the user has been doing with his or her computer, and that if the user makes any changes at all to the computer's hardware, it will be rendered unusable immediately. In short, that WPA is merely a way for Microsoft to gain and store personal information about the people who use Windows XP for commercial purposes. Fortunately, all of these rumours are false.

When Windows XP starts up, it simply checks that it is installed on the same computer it was installed on the last time it made the check. If Windows can't match the computer's hardware configuration to its record of it, the user is required to reactivate Windows. There is really nothing much more to it than that other than that the user initially has to activate his or her licensed copy of Windows online or by telephone. If it is done online, all that is required is to allow the process to go ahead.

Windows Vista Product Activation error message

Microsoft Knowledge Base article: 925616 - Error message when you start Windows Vista: "Your activation period has expired" - "When you start Windows Vista, you may receive the following error message: Activate Windows Now Your activation period has expired and Windows is no longer working. To use Windows you must activate this copy of Windows. Additionally, the taskbar does not appear. You have limited access to Windows Vista programs and features. Note When these symptoms occur, Windows Vista is running in Reduced Functionality Mode." -

How much longer will I be able to use Windows XP? - When will Microsoft's support for Windows XP and Product Activation end?


I have a Dell Latitude laptop PC running Windows XP Home that I bought just before Microsoft stopped selling Windows XP. It came with a free upgrade to Windows Vista. However, I don't want to upgrade to Vista because Vista taxes the hardware far more and I prefer Windows XP. I have read that Windows XP is near the end of its life. I am concerned about this because on two occasions I had to make use of System Restore to roll the system back to a previous date after a driver update degraded the system. On both occasions, I received a message that I had to reactivate Windows within three days. This has to do with the Product Activation that takes place online or that can be achieved by getting a reactivation code over the phone from Microsoft. So, I would like to know if Microsoft will be retaining Product Activation for Windows XP indefinitely.


You should not have had to reactivate after only using System Restore, because the activation process is only supposed to activated after a major upgrade of a piece of hardware, such as the computer's motherboard, that makes the system unrecognisable to the installation of Windows XP.

Many people are wondering if their Windows XP computers will stop working and are registering their worry in web forums, etc. Let me assure you that there is no need to worry. Microsoft only intends to end support and free security updates for XP in 2014. Moreover, it has no right to prevent any users from using software that they have paid for. Therefore, the product activation line will have to be kept open, or Microsoft will have to issue a fix that removes the need to activate. Indeed, Microsoft has hinted that issuing a fix is the most likely of the two options.

That said, I doubt very much that you will still be using your laptop after 2014. I always intend to go on using a version of Windows, but always give up after using it becomes impractical. That is, when new printers, etc., don't come with device drivers for that particular version of Windows, which is what happened when I gave up on Windows 98.

How to make sure that Windows XP is activated

If Windows XP doesn't nag you to activate it with Microsoft over the Internet or by telephone, it is already activated. Many pre-installed versions of XP would already have been activated when the software was installed by the computer's Original Equipment Manufacturer (OEM). Windows XP in such computers checks the BIOS to make sure that it is running on the same motherboard that was in the computer when it was installed. But if you are worried about exceeding the 30-day time limit that XP allows for activation to take place before it shuts down, you can check this by clicking Start => All Programs => Accessories => System Tools, and the choosing Activate Windows. This will tell you if XP has been activated.

If you don't have this link in the Start menu, entering the following command in Start => Run will provide you with the information - c:\windows\system32\oobe\msoobe.exe /a.

Original Equipment Manufacturer - OEM - Windows Vista

A version of Windows Vista that has a Product ID such as this one - 76588-OEM-0032903-02827 - is called an OEM copy that has been pre-installed by the computer's manufacturer. It can only be used on the same computer. If, say, a significant component, such as the motherboard, is changed, the PC cannot be used, because Microsoft's Product Activation deems that it is installed on a different computer. You would then have to buy a new licence for that computer.

However, it is known that some users have got around this limitation by calling Microsoft and reporting that their motherboards have died, so they had to replace them. It is Microsoft's policy to allow motherboard swaps in instances where a system is defective or has suffered a hardware failure. However, if you are really just an upgrader taking advantage of that policy, you shouldn't rely on it, because Microsoft may rule that you have to install the same make and model of motherboard so that none of the other components need to be upgraded. In that way, Microsoft can be reasonably sure that you have not just upgraded the computer.

Buying OEM versions of Windows Vista: the facts -

"Today Vista launches. I've received a number of e-mails from readers looking for more information on the black arts of the OEM edition, so here it is: my brief introduction to everything you need to know before going OEM." -

My Windows XP/Vista PC failed Windows Genuine Advantage (WGA) validation and produces this message: "This copy of Windows did not pass Genuine Windows Validation..."


The hard disk drive in my Windows XP PC was replaced by a computer repair shop after it started experiencing problems out of its warranty period. [This problem can also affect Windows Vista PCs.] It works properly now, but this message keeps coming up when I log on: "This copy of Windows did not pass Genuine Windows Validation and you have not yet resolved the problem. To protect your copy of Windows click Resolve Now." Doing that just logs into the system as usual.


When the hard disk drive was replaced, a copy of Windows [XP/Vista] must have been installed on the new drive. However, it looks as if a copy of Windows was installed that is not compatible with the Product Key (that provided on a sticker on the back of the PC, or is on the envelope of the Windows CD/DVD that came with it) - a pirated copy of Windows [XP/Vista] with a Product Key that is on Microsoft's list of pirated keys. When the Windows Genuine Advantage tool that is downloaded as an update ran automatically to validate the installation, it discovered the illegal copy and the validation failed.

If the PC came with a genuine Windows XP/Vista CD/DVD you have to use it to install Windows. You should run the disc by having it in the optical drive and then make use of its format feature to format the C: drive (the default location for an installation of Windows). You can then install Windows by running its setup procedure.

If the PC came with a system recovery disc, which restores the hard disk drive to the condition it was in when it left the factory, you can use it to do that. If the PC's recovery system is in a hidden partition on the hard disk drive, you won't be able to use it, because it is run from within the installation of Windows that was originally preinstalled at the factory. In that case, you might be able to obtain a recovery CD/DVD from the PC's manufacturer.

If there is a genuine sticker on the back or the side of the PC that has the Product Key on it, you should be able to use a compatible version of Windows XP/Vista (any Windows XP/Vista CD/DVD) with the key on the sticker. A compatible version means a Home, Professional or Media Center Edition of XP (or a Vista Home Premium, Vista Business, Vista Ultimate edition, etc.), which is named on the sticker. If the sticker has a computer manufacturer's name, or says OEMACT, or OEM, you must use a copy of Windows XP/Vista that has an OEM licence, which has the letters OEM in the Product Key, because the retail or corporate versions of Windows won't work with an OEM Product Key.

If a computer manufacturer is named on the sticker, or it says OEMACT, you should obtain an installation CD/DVD from that manufacturer, because it will validate the computer's BIOS Setup Program instead of requiring standard validation. However, if the OEM CD/DVD is not from the same manufacturer as the computer, it should install, but a phone call to Microsoft will be required to validate Windows. You will have to explain to the support staff why you had to use a different Windows CD/DVD. Since your setup is legitimate, you should be given a long code that you enter to validate the installation instead of validating online.

How to activate Windows XP and Windows Vista on the Internet

In Windows XP, the Windows Product Activation Wizard is located in System Tools. To open a system tools item, click Start => All Programs => Accessories => System Tools. Click on the appropriate activation icon, and then click Activate Windows.

To activate Windows Vista open Windows Activation by clicking the Start button in the bottom left-hand corner of the screen, then click Computer => Properties, and then click Click here to activate Windows now. Administrator permission is required. If prompted for an administrator password or confirmation, enter the password or provide confirmation. You can then select the method to use to activate. Note that if you chose to automatically activate Windows Vista online, automatic activation only begins trying to activate your copy three days after you log on for the first time.

Windows Vista Activation -

Troubleshoot activation problems [in Windows Vista] -

The articles focus on Windows Vista, but the same information applies to Windows XP and Windows 7 (release date, October 22, 2009).

There is not much difference between activation in Windows XP and Windows Vista, so I will only refer to it in Windows XP.

During the installation of Windows XP, the setup wizard requires the Product Key to be entered, which is usually located on the back of the Windows CD's case, or on a sealed, printed label inside the case. It is a 25-character alphanumeric code in five groups of five characters each - e.g., ABCDE-12345-FGHIJ-67890-KLMNO. You must not lose this number because you'll need it if you ever have to reinstall Windows. The Product Key is used by Windows to create the Product ID, which is unique to every licensed copy. The Product ID that Windows creates has 20 characters arranged in this form: 12345-123-1234567-12345. To find out what it is, right-click on My Computer, and click on Properties. The number is on the General tab of the System Properties window that comes up, under the Registered to heading.

Windows XP SP3 users will have 30-day's grace to enter a Product Key

January 2, 2008. - With Windows XP Service Pack 3 (SP3), Microsoft is changing its Product Activation policy to match that of Windows Vista, giving users a 30-day period of grace before they have to enter a Product Key. Windows XP SP3 is expected to be made available in the first half of 2008. Users who upgrade Windows XP SP2 to SP3 via the Windows Update service, will not have to re-enter their Product Key. The current versions of Windows XP require users to enter their Product Key during installation as part of the Windows Genuine Advantage (WGA) anti-piracy feature. Failure to do so halts the installation. Microsoft's site has this to say on the subject: "The operating system will prompt the user for a Product Key [30 days] later as part of Genuine Advantage."

If the copy of Windows XP has an OEM licence (which means that it is supported not by Microsoft but by the manufacturer of the computer, or by the private individual who built a computer and bought the OEM copy of XP with the qualifying item of computer hardware), the Product ID has the letters OEM in the alphanumeric number - e.g., 78967-OEM-8976543-98765. Note that an OEM copy of Windows XP entitles its owner to receive all of the updates and patches from Microsoft Update. Support means putting wrongs right or helping sort out problems, not the entitlement to updates.

There is more information about OEM Windows XP further down this page.

"For purposes of product activation only, a non-unique hardware identifier is also created from general information that is included in the system components. At no time are files on the hard drive scanned, nor is personally-identifiable information of any kind used to create the hardware identifier. Product activation is completely anonymous. To ensure your privacy, the hardware identifier is created by what is known as a "one-way hash". To produce a one-way hash, information is processed through an algorithm to create a new alphanumeric string. It is impossible to calculate the original information from the resulting string. The hardware identifier is used together with the product ID to create a unique installation ID. Whether you choose to activate by using an Internet connection or by speaking with a Microsoft customer service representative, the installation ID is the only piece of information required to activate Windows XP." - from Windows XP SP2's Help and Support.

How to activate Windows XP over the telephone

"If you do not have a modem or an Internet connection, you can activate your copy of Windows by calling a Microsoft customer service representative. Activating Windows is fast and does not require your name or other personal information. If you have not yet activated Windows XP, you can initiate activation at any time by clicking the Windows Activation icon in the system tray. Once you have activated Windows XP, this icon disappears from the system tray. If you choose not to activate now, reminders will appear periodically during the next 30 days. After that time has expired, you will be required to activate in order to continue to use Windows." - from Windows XP SP2's Help and Support.

Microsoft's customer service representative instructs you how to find the installation ID, which has to be supplied over the telephone.

To find out what other information is available in Start => Help and Support, just enter product activation in its Search box.


The End User Licence Agreement (EULA) has always stipulated that installation of a copy of Windows XP is only permitted on a single computer, which excludes having it installed on a laptop as well as a desktop computer. However, note that the licence for the MS Office suite allows its applications to be used on a laptop and a desktop computer. In short, WPA is a means of making sure that a single copy is not installed on more than a single computer. Therefore, during the first 30 days after installing Windows XP, Windows must be activated if the owner of the licence wants to keep using it.

If the 30-day period of grace expires and you have not completed activation, all of Windows XP's features will stop working except for the Product Activation feature.

Most of the time, Product Activation involves the computer running its activation process online. It sends information to Microsoft about the computer's hardware, after which Microsoft's site returns the release code which is recorded within the system. Thereafter, Windows XP checks every time it is started up to find out if it is running on the same hardware. If the hardware doesn't match sufficiently, the computer's owner can't do anything more with the computer than back up files until he or she telephone's Microsoft to explain why there is a difference in the computer's hardware. For instance, a valid reason could be that the computer broke down and had to be rebuilt. If Microsoft is satisfied with the reason, the user will be given a new release code that has to be entered manually to achieve the reactivation.

How to avoid having to reactivate Windows XP if you have to reinstall it and you have made no changes to the hardware

If you haven't backed up your Windows XP system, or haven't created a master image that you can restore in the event of an irrecoverable system failure, and you haven't made any changes to the hardware that would invalidate the old activation code and make it necessary to reactivate Windows XP, you can store the two files that contain the Windows Product Activation (WPA) data on a floppy disk, and copy them to the system after reinstalling Windows so that no activation is required from Microsoft's site or by telephone.

The two files are called Wpa.dbl and Wpa.bak. And they're located in the C:\Windows\system32 folder (if Windows is installed to its default Windows folder and not to a folder with a different name of the user's choosing).

In Windows Vista, there is a Wpa.dbl file in the C:\Windows\system32 folder, but it isn't clear from information on the web if it can be used to activate Vista in the same way as it can be used with Windows XP. However, I assume that the file serves the same purpose in both versions of Windows.

You should reinstall Windows XP. During the process, you should refuse the option to "Activate now". You should then restart the computer and press the F8 key to bring up the Advanced Boot Options menu, and then choose to boot into Minimal Safe Mode. You can then open My Computer, click on the A: drive and copy the two files on the floppy disk to the C:\Windows\system32 folder.

Note well that you should not do this if you have made changes to the system's hardware that would require Windows XP to be reactivated on the web or by obtaining the new code from Microsoft over the telephone.

The two files contain a description of the system's hardware and the activation code that Microsoft generated from its site or provided by telephone, both of which are encrypted. At each system start-up, Windows XP decrypts (unencrypts) the description and checks to make sure that the hardware matches the recorded description. The details that are recorded include the serial numbers of the hard disk drive(s), and the MAC address that every Ethernet network card has. A user therefore cannot copy the two activation files from a system that has the same hardware, because although the make and models of the hardware are the same, the identification numbers are different.

A newly installed copy of Windows XP allows its user to activate it automatically from Microsoft's site without having to obtain the activation code from Microsoft over the telephone. But if you attempt to reactivate the same copy of Windows XP within 120 days, you have to obtain the activation code over the telephone.

To do that you need to know what the Windows XP product key (also known as the CD key) is. It should be recorded on the licence sticker that is provided with with the Windows CD, which its user is supposed to stick on the computer's case. If this has been lost then it's not as easy as it was in Windows 95/98/Me to find out what the key is, because in Windows XP and Windows 2000 it is encrypted and not stored in plain text, as it is in the Windows 9.x versions. To find out what it is, you can use a utility specially designed to do so, such as the Belarc Advisor from Look under Downloads. When it is running, the Product Keys are under Software Licences (top, left-hand side).


For no reason, a message from Windows XP tells me that I need to reactivate Windows within 3 days because of "significant hardware changes"


For no apparent reason, when I log on to one of my desktop PCs that runs a legal copy of Windows XP SP1, I am stopped by a message that tells me I have to reactivate my computer within 3 days because there have been "significant hardware changes." I don't use this PC very often. It has not been opened since I got it five years ago, so what's up with this Product Activation thingy?

It's an old PC so it looks as if the battery that keeps the configuration data in the BIOS active even when the PC is switched off has died or is weak. Consequently, the configuration data has had to be rediscovered from the CMOS chip that contains the BIOS data. The BIOS has had to 're-enumerate' its hardware at boot-up. Several things, including an errant keystroke or an ageing BIOS battery, can trigger this re-enumeration. Windows keeps its Product Activation information on board, so it may have reacted to the hardware being re-detected and reconfigured. Replacing the BIOS battery will probably fix the problem. The battery is cheap. Just remove it and take it into a PC shop to obtain a replacement, which should last another five years. Click here! to go to the information on the BIOS battery on this website. Instructions are provided on how to remove it.

My PC is stuck in a Product Activation loop


While I was visiting the Microsoft Update site to download an update for Windows Media Player, I was required to validate my copy of Windows XP through the Genuine Microsoft Product page, which I did. However, when I started the PC the next day, I was greeted by a message saying that my copy of Windows XP must be activated and asking me if I wanted to do it immediately. I clicked Yes, but then a screen came up that told me that the product was already activated. When I clicked OK, I was returned to my logon screen. When I logged on, the process repeated itself. I can no longer get into my PC. I can only start up in Safe Mode.


The Product Activation data is kept in the wpa.dbl file in the C:\Windows\System32 folder. If you have access to a master image or backup copy of that file that was created when the PC was working properly, you can boot into Safe Mode, open Windows Explorer, and copy the wpa.dbl file into the C:\Windows\System32 folder. Reboot and you should be back in business. If that doesn't work, boot into Safe Mode again and delete the wpa.dbl and wpa.bak files, and reboot. With those files no longer there, Windows XP will have to reactivate, because it reads them when it checks to see if it is activated.

I want to upgrade two Windows XP PCs to Windows XP SP2. Can I use the Upgrade version of SP2 on both of them and just enter their own Product Keys?


I have Dell desktop and laptop PCs. I want to perform a clean install of Windows XP on both machines. The Windows CDs are Service Pack 1 (SP1), and I want to update the installs to Service Pack 2 (SP2). I have an Upgrade version of Windows XP SP2 on a CD. Is it possible to use the SP2 CD on both PCs by entering their Product Keys? Or, are Product Keys exclusive to the CDs that they come with?


It would work fine as long as the Product Key matches the CD's type ( an Upgrade version Product Key for use with an Upgrade version CD). The key is coded to match the CD's type. Nothing is hard coded into the actual code on the disc. But you can't use an OEM Product Key from Dell with a retail version of XP SP2, because OEM and retail versions are two different types of CD's. Dell always supplies an OEM version of XP with its PCs.


Windows Genuine Advantage (WGA) does not validate a copy of Windows XP

If the Windows Genuine Advantage (WGA) validation process does not validate a copy of Windows XP as expected when you are attempting to obtain Microsoft software that requires it and a message comes up that says: "Windows Activation Required. Windows must be activated in order to determine if the Windows product key installed on this computer is genuine", the most common reason that this happens is because the Wpa.dbl file has been set to read-only. To put that right, go to the Start => Run box. In the Run box, enter: attrib -r %windir%\sytem32\wpa.dbl, then click OK. Alternatively, use Windows Explorer to navigate to the Wpa.dbl file in the C:\Windows\system32 folder, right-click on the file and select Properties. On the General tab, under Attributes, make sure the Read-only checkbox is not checked. If this doesn't work, read MS Knowledge Base article 916247 - Windows Genuine Advantage does not validate a copy of Windows XP - - on how to use the WGA Diagnostics Tool to determine why the copy of Windows has not been validated.

Which items of a computer's hardware does Product Activation list and check?

WPA checks ten categories of hardware:

1. - The display adapter - the video card.

2. - SCSI adapter - if present it allows the use of SCSI hard drives and other SCSI devices.

3. - The IDE adapter (the motherboard's IDE hard drive controller)

4. - Network adapter (NIC) and its MAC Address

5. - RAM - amount and range (i.e., 128 to 256MB, 256 to 512MB, etc.)

6. - The processor's type - the make and model of processor(s)

7. - The processor's serial number [not all processors have serial numbers, and some that do allow it to be disabled so that it can't be read]

8. - The hard drive device

9. - The hard drive's Volume Serial Number (VSN)

10. - The make and model(s) of CD/DVD drive(s) installed.

The make and version of the BIOS doesn't count at all. The product-activation code is only locked on to the BIOS with the OEM version of Windows XP that the major computer manufacturers pre-install on their computers.

The activation process calculates and records a number based on the first device of each type that was found during setup. The number is stored on the computer's hard drive. During the actual online activation the number and the Product ID number, which Windows creates from the 25-character unique Product Key that every non-corporate copy of Windows XP has, are returned to the activation centre. If you bought a brand-name PC, the Product Key is usually attached somewhere on the computer's case. If you have bought a retail or OEM version of XP, the Product Key is supplied with the CD. If Service Pack 1 or Service Pack 2 has been installed, the entire Product Key is also transmitted in order to check it against a list of known pirated Product Key numbers.

Microsoft keeps a record of the information it collects on every licensed copy of XP so that no one can install it on another computer and activate it. It would be a prohibitively costly business to create a computer that has all of the same hardware, MAC Address, the Volume Serial Number, processor serial number, etc., as another computer in order to be able use one copy of XP on more than one computer.

If you format the hard drive (usually the C: drive) and reinstall of Windows, reactivation is usually required because the new installation contains no activation information. However, that can be avoided if you follow the advice provided in the blue table above. But if you do reinstall and reactivate XP, if the hardware is unchanged or substantially the same, the activation will go ahead as easily as if that copy of Windows has never been activated before.

How does the process work out what substantially the same means if you have made changes to the system? Well, believe it or not, it asks for a certain number of yes answers to questions it poses on each of the ten categories of hardware that are taken into account. For example, it checks the Volume Serial Number of the hard drive with the current one. If it has changed that is a No answer. Seven Yes votes are required in order to avoid reactivation if the system has changed. A network card (NIC) that was present, and is still present, counts for three Yes votes. Minor adapter cards, such as a sound card, don't count at all. You can install as many of them as you like without having to reactivate Windows XP.

In other words, the same motherboard, RAM, processor, and NIC, provide enough Yes votes to enable you to make any other changes without having to reactivate. If you change the device in any particular category, you have lost its Yes vote, but that category of device can't lose a Yes vote more than once, so it can be changed as much as you like without a penalty thereafter. For instance, after initially changing the video card, you could install a new video display card every month for as long as you like without being penalised in the vote count. However, if you boot the system in which a device that has been disabled, the device won't be found during the check that takes place every time the computer is started. For instance, if you disable the network connection that uses the network interface card (NIC) and then reboot the system, the missing three votes that it provides can make reactivation necessary if the count of Yes votes goes under the seven required.

What happens if too many changes are made to the system?

In the original version of Windows XP, if the computer is started and the checking process doesn't produce the required seven votes, the system will only start up in Safe Mode.

You will be required to reactivate by making a telephone call to Microsoft. You'll have to write down a 50-digit number, call the activation centre on a freephone number that is provided, read and repeat the number you recorded, and then explain why you made the changes to the system. If satisfied by your explanation, Microsoft's customer representative provides you with a 42-digit number that you enter as required by the product activation feature. This will reactivate your copy of Windows. The process is easier if you have installed Windows XP Service Pack 1 (SP1) or Service Pack 2 (SP2), which incorporates SP1. The system continues to boot normally for three days, during which time you can contact the activation centre via the Internet. If the extra changes have been removed, or if 120 days have passed since the manual activation, henceforward you'll be able to use the automatic process online to reactivate Windows XP.

What happens if the hard disk drive is formatted in order to reinstall Windows XP?

During the creation of the Product ID, the serial number of the hard disk drive itself, and the Volume Serial Number (VSN) of the drive or partition that Windows XP is installed on are used.

The VSN changes when that drive/partition is formatted.

If you need the vote, some freeware utilities called Volume ID can restore the original VSN. If the following two links to two different free utilities no longer work, you can find your own download sources by entering "volume id", as is, as the search query in a search engine.

Sysinternals was an independent organisation that provided grea free utilities, but it is now owned by Microsoft. Visit for the great free utilities, which should include Volume ID.

Another way to obtain the same result would be to delete the Windows XP files from the hard drive before reinstalling instead of reformatting.

The VSN also changes if you convert a partition formatted to use the FAT32 file system to use NTFS instead. Therefore, if you upgrade a system that uses FAT32 to Windows XP and want to convert to using its NTFS file system, which is not available in Windows 95/98/Me, you should do the conversion before activating the system. If you have already activated, make use of one of the Volume ID utilities. If you are doing this after activation, first back up the Wpa.dbl and Wpa.bak files, as described in the blue table above, and, after completion of the conversion, restore these files and reboot the system.

If you install a new hard drive and reinstall Windows XP to a new partition, you have lost two Yes votes. But if you install a new hard drive and copy the original partition on to it with an imaging program (such as Norton Ghost), and keep the original hard drive installed as a secondary drive, you won't lose the two votes because the old hard drive will be found during the hardware check if the partition hasn't been reformatted. In other words, adding a new drive to the system doesn't lose votes as long as the old drive still has the same VSN. Moreover, with regard to removable hard drives, as long as Windows XP is still present on the drive that was installed when the prevailing WPA calculation took place, a removable hard drive used to store data or back-ups is not taken into consideration in that calculation.

The position with regard to a swappable hard disk drives or external hard drives

Provided an external hard drives, or a swappable hard drives, are used as secondary drives to store data, external or swappable drives do not enter into the WPA calculation.

What happens if the motherboard is changed?

Unless the same make and model of motherboard is installed, replacing a computer's motherboard changes the IDE controller, which has a vote that becomes No if it is changed. A new motherboard usually means that a new, faster, processor is installed. If the existing processor is one of those that has a serial number (e.g., a Pentium III), then you lose a vote even when you change to a processor that has no serial number, such as an Athlon XP. If you add RAM, or the motherboard has an inbuilt SCSI adapter, that makes four or five categories that have changed to voting No. The situation worsens considerably if the motherboard has an inbuilt NIC, because its MAC Address has a vote, and if it has an inbuilt video chip, because the display adapter has a vote.

In short, if you change the motherboard, the chances are that you'll have to reactivate XP, because most modern motherboards have several categories of device that have a vote. But fear not, telephone reactivation was created in order to make reactivation possible in this kind of situation.

If you don't want to have to use telephone reactivation, it is always best to make any hardware additions secondary ones. For example, if you add another hard drive or CD/DVD drive, make sure that it uses the secondary IDE channel on the motherboard, because WPA always uses the first-order components in its calculations.

XPInfo from can display which categories are currently casting Yes votes during the WPA check. You can then calculate how many votes you'll have if you make any changes. As long as you still have seven votes after the changes, you'll be able to use the web to reactivate XP.

Will a time ever come when reactivation won't be necessary?

The licence for Windows XP lasts for as long as the product can be used, but Microsoft has set a date when support for the product will end. When Microsoft effectively abandons XP, the company has said that if it ever becomes uneconomic to keep the activation system for XP going, users will be provided with the means to disable the need to activate, but, by then, no new device drivers for new hardware will be available, and no one will want to use XP with new hardware anyhow.

That said, at present, if you don't need to contact the activation centre during the 120-day period after a telephone reactivation (made necessary because of the number of changes made to the system), this means that any changes you have made during the 120 days have been acceptable, the slate is then wiped clean, and you can start again using the current hardware as the new basis for making additional changes. Moreover, if you buy a new computer, if you remove a retail copy of Windows XP from the computer that is being sold or scrapped, you're entitled to install the same copy of Windows XP on the new computer. However, you'll have use the telephone option and explain the situation to Microsoft's customer service.

OEM versions of Windows XP

If necessary, click here! to go to information on the OEM versions of Windows XP on this site.

There are two versions of OEM licences for Windows XP.

For one of them, the OEM CD is purchased with a qualifying item of computer hardware. Windows XP can be reinstalled and reactivated indefinitely as with the retail version as long as it is done on the original computer. The licence (license) cannot be transferred to a different computer. It is activated as usual, either online or by telephone, but if it were to be installed on hardware deemed as being not sufficiently the same, the activation would be refused full stop (period) for failing to meet the terms of the licence.

However, if the motherboard is replaced, read the information provided in the next item on this page.

In the other type of OEM licence, Windows XP is pre-installed by a major computer manufacturer, such as Dell. In this case, instead of activation, the system is locked to the make and version of the BIOS on the motherboard. Every time the system is booted, Windows checks to make sure that the BIOS is the same. As long as that is the case, the rest of the hardware components can be changed. However, if the motherboard is replaced, it must be with one that has been supplied by the original PC manufacturer.

If a BIOS-locked copy of Windows XP is installed on a motherboard and the BIOS lock fails, the system will go through the normal Product Activation process at startup. However, note well that from March 1, 2005, the Product Key supplied on a label by the computer manufacturer, and used for the initial installation, won't be accepted for activation. A new copy of Windows XP, with a licence allowing installation on a different computer, will be needed. This means that any replacement motherboard, or upgrade to its BIOS, must be supplied by the original manufacturer in order to ensure that the BIOS lock is put into effect.

Microsoft ends OEM Windows XP Product Activation over the Internet

March 6, 2005. - "At the start of this month, Microsoft made changes to the way that Windows XP can be activated on PC that have an Original Equipment Manufacture (OEM) licence (US: license). OEM PC's are those of large computer manufacturers, such as Dell, HP and others. According to Microsoft, Internet Activation will no longer be available for systems bought from the top 20 computer makers starting this month. [I.e., Windows XP has to be activated by telephone.] In the next quarter the ban on Internet Activation will be extended to include all pre-activated Windows PCs. Microsoft explains this as a measure against piracy. The problem is that OEMs can install Windows XP, and bypass product activation (via an approved method). But the Certificate Of Authenticity (COA) labels on these PCs could easily be copied and used to activate another copy of Windows XP using Internet activation. COAs have also been reported stolen, and sold on to other (smaller) PC manufacturers, and unscrupulous PC makers have also been known to use one COA on multiple systems. So now when a user of a pre-installed Windows XP [system] wants to re-install the OS, he or she will be redirected to call Microsoft customer support, who will ask a number of questions to check if their copy of Windows XP is legitimate. I don't think this will be a problem for most users. The larger OEMs are authorized by Microsoft to customize their branded re-installation and recovery media [System Recovery CDs that restore the system to the state it was in when it left the factory], so that if Windows XP is re-installed [by making use of the recovery system] on the hardware it shipped on, it will not require end-user activation. This policy change also doesn't apply to the "retail" version of Windows XP." - From a Help With Windows Newsletter

Windows XP Service Packs 1 and 2

Windows XP Service Pack 1 (SP1) won't install at all on systems that have used one of two well-known pirated Product Keys, and a much wider range of pirated and cracked keys will result in access to Microsoft Update being refused. These limitations have been increased by Service Pack 2 (SP2). The installation of SP1 can detect and remove a number of cracks that are used by pirates to circumvent the need to activate. If such a software crack is detected, the system has to be reactivated. However, legitimate installations of Windows XP don't need to be reactivated after installing SP1 or SP2 or SP3, the last Service Pack for Windows XP.

For more information on this topic, read Microsoft's article Service Pack 1 Changes to Product Activation. -

Windows Product Activation on a computer with an OEM licence (US: license)

My OEM copy of Windows XP can't be reactivated after I replaced the motherboard in my computer


My OEM copy of Windows XP can't be reactivated after I replaced the motherboard in my computer. Why not?


New brand-name computers (Dell, HP, Gateway, etc.) come with Windows XP preloaded that has an (Original Equipment Manufacturer) OEM licence. The OEM licensing system is different to that of the retail packaged version of Windows XP. The OEM licence does not allow Windows XP to be transferred to a new computer; the retail licence does allow such a transfer. OEM copies are only licensed for use on the new computer on which they were originally installed.

Many OEM copies installed by the major manufacturers (Dell, HP, Packard Bell, etc.) use a system called System Locked Pre-Installation (SLP) that doesn't match any hardware on start-up. It looks for a special signature in the BIOS setup program instead. If the computer's installation Windows XP has a file called oembios.bin, then it has SLP-activated OEM copy.

If a BIOS-locked copy of Windows XP is installed on a motherboard and the BIOS lock fails, the system will go through the normal Product Activation process at startup. However, note well that from March 1, 2005, the Product Key supplied on a label by the computer manufacturer, and used for the initial installation, won't be accepted for activation. A new copy of Windows XP, with a licence allowing installation on a different computer, will be needed. This means that any replacement motherboard, or upgrade to its BIOS, must be supplied by the original manufacturer in order to ensure that the BIOS lock is put into effect.


Some OEM copies of Windows XP, such as an OEM copy purchased with a qualifying item of computer hardware, will have been activated individually in the same way as the packaged retail version is. If this is the case, the OEM copy behaves in the same way as the retail version. That is, after installation, it examines the following ten components:

1. - The display adapter (video/graphics card). 2. - The SCSI adapter (disk-drive adapter). 3. - The IDE adapter (disk-drive adapter/controller). 4. - The Mac Address of network interface card (NIC). Mac address. 5. - The RAM - the memory range (0 - 64MB, 64MB - 128MB, etc.). 6. - The type of processor (make and model). 7. - The processor's serial number - if it has one that can be read. 8. - The hard disk drives installed. 9. - The volume serial number of the master boot hard disk drive (more on this below). 10. - The CD/DVD drives installed.

Note that "9. - the volume serial number of the master boot hard disk drive" is not the HDD's serial number. It is the volume serial number that is created when the drive is formatted.

In Windows XP, enter cmd in the Start => Run box. Entering the VOL command shows the volume serial number. If you want to set the new master (boot) hard disk drive to the same volume serial number as the old one, you can use a free Sysinternals utility called volumeid.exe.

Sysinternals was an independent organisation but it is now owned by Microsoft. Visit for the great free utilities.

Each time Windows XP starts up, it checks if the computer has the same (or acceptably similar) hardware that it listed when it was activated. If it detects that substantial changes have taken place - the system is "substantially different", then it requires the user to reactivate it.

The network card (NIC), which provides a unique Mac address, is given three times the weight of any other change to the system. If the computer can be docked with another computer (attached to it electronically so that files can be transferred between them), it is only allowed nine instead of ten changes in the hardware configuration before it has to be reactivated.

If the computer can't be docked to another computer and it has the same network card, six or more of the ten listed components would have to be changed before reactivation would be required. But if a network card is replaced, or was never a component in the computer, four or more changes (including the replacement of the network card) would require reactivation to take place.

Thus, if an OEM copy of Windows XP isn't a System Locked Pre-Installation (SLP), it is possible to make several changes to the hardware without having to reactivate. Indeed, provided that the same network card, video card, and master hard disk drive are installed, you can change any of the other components. Additional CD/DVD drives can be added without the product activation to be reactivated.

Microsoft takes the view that if the computer has an OEM licence and you upgrade the computer's motherboard, you have a new computer and you are therefore required to buy a new licence.

With such an OEM licence, Microsoft takes the view that it is the computer's motherboard that defines it. You can change any of the other hardware components and Microsoft considers that it is the same computer. However, if you change the motherboard, Microsoft deems that you have a new computer, and therefore you can't reuse its OEM licence. However, Microsoft has now recognised that there are occasions when a motherboard fails irredeemably and has to be replaced. Since motherboards have such a short shelf life (new models are appearing all the time and older models are no longer available), the computer's owner might have to purchase a motherboard that doesn't have the same set of components (chipset, inbuilt network card, etc.) as the failed motherboard, Microsoft's policy is therefore to allow a computer owner whose motherboard has failed to reactivate an OEM copy of Windows XP after installing a replacement motherboard.

However, in order to achieve that, the computer's owner will have to explain the situation to one of Microsoft's representatives over the telephone. If the representative accepts the validity of the information, the owner has to go through the process of reactivation over the telephone, which involves having to write two sets of code down. The process is described under What happens if too many changes are made to the system? on this page.

Note that many resources have reported that only hardware changes that have been made within 120 days from any particular date are counted in the determination of whether or not reactivation is required. However, this has not been confirmed as a fact by Microsoft. Apparently, Windows XP wipes the slate of the number of hardware components changed clean every 120 days if the number of changes allowed haven't been exceeded. This site - - covers the technical details involved in Windows Product Activation. It also provides a free utility called XPInfo that calculates how many of the allowed changes have already been made.

MS Knowledge Base articles on Microsoft Windows Product Activation in Windows XP and Windows Vista

Click on the article's reference number to go to that article on Microsoft's website

Error message when you start Windows Vista: "Your activation period has expired" - When you start Windows Vista, you may receive the following error message: "Activate Windows Now Your activation period has expired and Windows is no longer working. To use Windows you must activate this copy of Windows." - Additionally, the taskbar does not appear. You have limited access to Windows Vista programs and features. Note When these symptoms occur, Windows Vista is running in Reduced Functionality Mode.
Error message when you start Windows Vista: "Your activation period has expired" - This article describes a problem in which you receive a "Your activation period has expired" error message when you start Windows Vista. A resolution for this problem is included.
Description of Microsoft Product Activation
How to activate Windows XP
How to obtain additional licenses for Windows XP
Error message when you try to activate Windows XP: "local scripting has been disabled on this computer" - When you try to activate Microsoft Windows XP, Microsoft Product Activation may be unsuccessful, and you may receive the following error message: Activate Windows cannot run because local scripting has been disabled on this computer. Scripting may have been disabled for virus prevention or as a security measure. Once local scripting has been enabled, run Activate Windows again.
Blank Activate Windows page in the Windows Product Activation Wizard
You receive a "Please wait while the wizard initializes..." error message when the Activation Wizard dialog box appears
How to change the product key at the time of activation

Other sources of information on Windows Product Activation

Click the following links to go to other articles on the subject:

Windows Vista Activation -

Microsoft Product Activation -

Troubleshoot activation problems [in Windows Vista] -

Frequently asked questions about Microsoft Product Activation -

Microsoft Windows XP Product Activation -

More On Windows XP Product Activation - and

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