We have all seen and read about problems with WGA before and it seems some users are currently encountering a new bug in Windows XP or Windows Server 2003 which prompts for activation every time the computer is started even if the operating system has been activated before.
Microsoft states that the cause of the problem is that a script that is running on the computer “interferes with Windows activation”. No word on what script is interfering with the activation and how it was installed on the computer is provided by the company.
It is unclear if Microsoft is referring to a third-party script that is blocking Windows from remaining activated or if a first-party script that is part of the operating system is causing the issue.
Microsoft is offering a guided help file and a manual solution to fix the problem that prompts the user to activate his operating system even if it was successfully activated before.
This article contains information to help you resolve a Windows product activation problem. You may be prompted to activate Windows every time that you start the computer. You experience this problem even if you have already activated Windows. This article describes how to remove a script that may interfere with Windows activation. To do this, you must start the computer in safe mode, modify the Windows registry, and then restore the Windows product activation file. Then, you can reactivate Windows. After you follow these steps, you are no longer prompted to activate Windows when you start the computer.
The guided help consists of a tool that users need to download to their system to resolve the problem.
The manual solution could take some time though. It consists of nine steps that involve deleting settings in the Registry, deleting files on the system and activating Windows again as the last step. While it will take more time to complete, it gives you full control over the process. (via My Digital Life)