Windows Activation Non-Exsistant

Sorry, folks, this is the best place I could find for this. I don't really know any good Windows forums, and since this is Windows XP Pro running on a Mac Pro this page seemed appropriate enough . . .

Anyway, Windows decides to fail and corrupt for no reason every six months on my Mac Pro (system info in the signature.) This time, when I reformatted and reinstalled Windows, the "Activate Windows" application never opened. According to Microsoft, it should be located in Start->All Programs->Accessories->System Tools->Activate Windows. It is not there for me.

I've done this many times before, and my only real question is: where is the executable for the "Activate Windows" application located? All I need to do is open it, and I should be good from there.

Thanks in advance.