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More On Windows XP Product Activation

By: Arie Slob

Windows XP I have already explained the basics of Windows Product Activation (WPA) in this article. Now lets have a look how this will work in "real-life", and also note some changes Microsoft made to WPA.

Product Activation and volume licenses

Windows XP upgrade licenses acquired through one of Microsoft's volume licensing agreements, such as Microsoft Open License, Enterprise Agreement, or Select License, will not require activation. Installations of Windows XP made using volume licensing media and volume license product keys (VLKs) will have no activation, hardware checking, or limitations on installation or imaging.

Microsoft also offers smaller companies the ability to acquire volume licenses at a discount under the Microsoft Open License program. Customers can qualify for Open License by purchasing as few as five product licenses. Almost all but the smallest businesses should be able to qualify for Microsoft Open License.

Product Activation and new pre-loaded (OEM) PCs

This will cover the majority of people (according to Microsoft upwards of 80%), when customers acquire Windows with the purchase of a new computer. Most new computers pre-loaded with Windows XP will not require activation at all. Microsoft provides OEMs with the ability to "pre-activate" Windows XP in the factory, so that end users will never have the need to activate their copy of Windows XP.

"Pre-activation" of Windows XP by the OEMs (Original Equipement Manufacturers) will be done in one of two different ways, which are up to the OEM to choose from. One way to "pre-activate" Windows XP uses a mechanism which locks the installation to OEM-specified BIOS information in the PC. This method of protection is called "System Locked Pre-installation," or SLP. OEMs have used a similar technology for years with the CDs they ship to reinstall Windows on their computers.

SLP uses information stored in an OEM PC's BIOS to protect the installation from casual piracy. No communication by the end user to Microsoft is required and no hardware hash is created or necessary. At boot, Windows XP compares the PC's BIOS to the SLP information. If it matches, no activation is required.

Every single piece of hardware could be changed on a PC with SLP and no reactivation would be required - even the motherboard could be replaced as long as the replacement motherboard was original equipment manufactured by the OEM and retained the proper BIOS. In the unlikely scenario that the BIOS information does not match, the PC would need to be activated within 30 days by contacting the Microsoft activation center via the Internet or telephone call.

The second way OEMs can use to activate Windows XP is by contacting Microsoft in the same way a user would activate. Activation done in this way is the same as activating a retail version of Windows XP.

Product Activation on retail copies

When you install a retail copy (full version or upgrade) of Windows XP, product activation is a mandatory step. If you don't activate Windows XP within 30 days, you will have to activate it on the next startup. Activation can be done over the Internet (preferable) or via telephone. For some more information read this article.

Product activation relies on the submission of the Installation ID which is comprised of two different pieces of information - the product ID and a hardware hash

Hardware used

Microsoft have listed the hardware components it uses to create the hardware hash, which is part of the Installation ID. The hardware hash is an eight byte value that is created by running 10 different pieces of information from the PC's hardware components through a one-way mathematical transformation:

  1. Display Adapter
  2. SCSI Adapter
  3. IDE Adapter
  4. Network Adapter MAC Address
  5. RAM Amount Range (i.e. 0-64MB, 64-128MB, etc)
  6. Processor Type
  7. Processor Serial Number
  8. Hard Drive Device
  9. Hard Drive Volume Serial Number
  10. CD-ROM / CD-RW / DVD-ROM

Additionally, whether or not the PC can be put into a docking station or accepts PCMCIA cards is also determined (the possibility of a docking station or PCMCIA cards existing means that hardware may disappear or seem changed when those devices are not present). Finally, the hardware hash algorithm has a version number.

Hardware Changes

Windows XP checks to see that it is running on the same or similar hardware that it was activated on. Reactivation is required if Windows XP detects that the hardware has changed "substantially". This check is performed after the SLP BIOS check discussed above, if the SLP BIOS check fails. This means that if your PC is pre-activated by the manufacturer, using the SLP pre-activation method, all the components in the PC could be swapped (including the motherboard, so long as the replacement motherboard was genuine and from the same OEM with the proper BIOS).

Microsoft uses different definitions for "substantially" changed. First there is a difference for PCs that are configured to be dockable. Additionally, the network adapter is given a superior "weighting.".

In a dockable PC, if a network adapter exists and is not changed, 9 or more of the other above values would have to change before reactivation would be required. If no network adapter exists or the existing adapter is changed, 7 or more changes (including the network adapter) will require a reactivation.

If the PC is not dockable and a network adapter exists and is not changed, 6 or more of the other above values would have to change before reactivation would be required. If a network adapter existed but is changed or never existed at all, 4 or more changes (including the changed network adapter if it previously existed) will require a reactivation.

The change of a single component multiple times (e.g. from display adapter A to display adapter B to display adapter C) is treated as a single change. The addition of components to a PC (adding a second hard drive) which did not exist during the original activation, would not trigger a reactivation. Reactivation would not be triggered by the modification of a component not listed above.

Reinstallation of Windows XP on the same or similar hardware and a subsequent reactivation can be accomplished an infinite number of times. Finally, the Microsoft activation clearinghouse system will automatically allow activation to occur over the Internet four times in one year on substantially different hardware. Every 120 days, the current configuration of a user's PC will become the new "base," so to speak. This means (for example) that on a non-dockable PC you could change 8 of the above parts without a reactivation. After 120 days, you could again change 8 parts. This last feature was implemented to allow even the most savvy power users to make changes to their systems and, if they must reactivate, do so over the Internet rather than necessitating a telephone call.


The vast majority of end users will never see activation, either on first boot or with substantial hardware upgrades. For those users whose new PC requires that Windows XP be activated or who acquire Windows XP through retail, activation will most likely be a one-time occurrence that.

I know that many people are not too happy about product activation, simply because over the years we have been used to buy one copy of the software, and use it on all our PC's. That this is an illegal practice, and is against the EULA (End User Licence Agreement) never bothered most people. But now Microsoft is putting in place a system designed to reduce this type of "casual piracy".

Service Pack 1

See Changes to Windows XP Product Activation in Service Pack 1.

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