Ive recently had a problem with my pc and have tried system restore (and while in safe mode)however whenever i try it, it says it is unable to do it and no changes have been made (have tried several restore points). I am thinking that i need to reinstall windows, however, have lost my product key. I downloaded several programs that apparently tell you your windows xp product key however they all come up with different keys ??? any advice on what to do?