One of the major change to Windows XP SP3 is the fine tuning to Windows Product Activation (WPA) feature in Windows XP. Prior to Windows XP SP3, installation of new Windows XP operating system requires users to enter a valid and genuine product key during setup process. Wrong, invalid or no product key input will stop or halt the installation process. Microsoft plans to change the product key requirement of Windows XP to the same with Windows Vista, where users can skip entering the serial key to a later stage with grace period that allows users to evaluate or try out the OS. Windows XP SP3 Overview documents the plan of the WPA change.
As in Windows Server 2003 SP2 and Windows Vista, users can now complete operating system installation without providing a product key during a full, integrated installation of Windows XP SP3. The operating system will prompt the user for a product key later as part of Genuine Advantage.
As with previous service packs, no product key is requested or required when installing Windows XP SP3 using the update package available through Microsoft Update.
Note The Windows Product Activation changes in Windows XP SP3 are not related to the Windows Vista Key Management Service (KMS). This update affects only new operating system installations from integrated source media. This update affects the installation media only and is not a change to how activation works in Windows XP.
However, when installing fresh Windows XP SP3 from clean state with a slipstreamed Windows XP installation CD with SP3 integrated, it appears that the setup process still prompt, and require users to enter a product key, compulsorily.
If the users attempt to leave the product key fields or boxes blank, and press the “Next” button to continue the Windows XP setup installation process, the setup prompts an error message saying product ID entered is not valid.
It’s unclear if Microsoft has dropped the change on Windows XP SP3, or the change to product key requirement does not been included on the Windows XP SP3 code bits, which will be included on Microsoft own integrated Windows XP SP3 CD, causing all user self slipstreamed versions Windows XP with XP SP3 files installation CDs do not reflect the change. As Microsoft hasn’t seem to release any official Windows XP with SP3 integrated CD image yet, this guess can only be verified when there is one.
Beside, there is possibility that the change on WPA only affect certain editions of Windows XP. Most user made integrated Windows XP SP3 ISO image is making use of corporate version which requires VLK (volume license key), which does not necessarily require a delay in entering product key during installation. Probably only retail version of Windows XP SP3 will have the ability to delay product key insertion and activation to use as trial. Again, the guess can only be verified when Microsoft releases or somebody leaks an official full integration Windows XP SP3 CD or image.
But, with Windows XP out of shelf (stop selling) soon, who really cares?
Update: As speculate, only Windows XP integrated SP3 retail CD can skip entering product key during setup.