If you haven't deleted
,there might be some hope of recovering.
Anyz, there is a possiblity of a virus roaming in your system. Well, if the total system looks screwed up, then try a 'repair' using windows XP disc. I would definetly go with a format and reinstall.
p.s: before you try any of the above, please make a virii/adware/spyware scan -if possible