When requesting a download from the Windows Update Web site, or from the Microsoft Download Center, you are prompted to complete the WGA (Windows Genuine Advantage) validation check to validate your copy of Windows XP. If you select Yes, please validate Windows and take me to the download and press Continue, you receive:

Windows Activation Required
Windows must be activated in order to determine if the Windows product key installed on this computer is genuine.

When you run %SystemRoot%\system32\oobe\msoobe /a to active Windows, the Activate Windows dialog does not appear.

This behavior will occur if the %SystemRoot%\system32\Wpa.dbl file has the read-only attribute set.

To workaround this behavior:

1. Open a CMD.EXE Windows.

2. Type the following command and press Enter:

attrib -r %SystemRoot%\system32\Wpa.dbl

NOTE: See What is the Windows Genuine Advantage program?