Very Strange
Just got back from a computer-less vacation ... and just saw your question.
I hope you've resolved this by now.
If you can get into Safe Mode, when you do, XP will ask if you really want Safe, or want to Restore, using System Restore.
At that point, you choose System Restore and select a Restore Point, then let it fly.
Under most circumstances, it should take you back to that point with no problems.
Again, I hope you've fixed this by now ...
-a.