This is definitely time to perform major backups!! Invest in an external or at least another internal HD... make it dedicated file storage for photos/music/data! That way.. if the OS gets hosed, you dont loose anything!

Its standard practice these days to make more than 1 partition... but 2 HDs is way better incase of failure.

Good luck tho, a XP recovery or repair should help you out... but you'll have to re-install all the service packs and patches!