I see that thing on 2 computer !
On one I had to re-install XP,
On the other, I did that :
- Boot on your XP install cd
- Choose repair
- When you are on the command line (c:\>WINDOWS>) type :
- fixboot c: (enter) --> y (yes)
- When it's finished type chkdsk c: /P /R (enter)
It will take a couple of minute to do the second operation but after that it will be repaired and you don't have to re-install.
But if one day you can install windows 7 64 bits !!