Fix activation loop in WinXP

Windows XP sometimes get stuck in a neverending loop where it thinks it needs to be activated, yet it already is activated which makes it impossible to reactivate. In order to fix this the following can be done. Boot in safe mode by pressing F8 on startup and open a command prompt and type the following:

rundll32.exe syssetup,SetupOobeBnk

Then reboot and it should be unstuck.