Vista repair.


Ok, so I am trying to repair my vista. When I Get to the screen to select vista to repair, it says it can't recognize that version or something along those lines. So I have two questions. To start, this is not the disk that came with my computer (it belongs to a relative and I'm borrowing it). It is a vista upgrade disk but if it were perhaps from a different version of vista would it not work? My other question is, if I totally reinstall windows is there any way to retrieve my files? Any help would be appreciated. P.S. I am typing this on my iPod and it is quite frustrating, so I am sorry if this is unclear or if there are any spelling errors.
Thanks for the advice. I have vista home premium, is that the 64 bit? This disk I have is a 32 bit, that might be the problem.