Have a PC with Vista that reboots right before login. The Windows loading bar show up, then it shows a black screen with the cursor in the middle and after about 30 seconds the computer reboots. Booting into safe mode does the same (restart after 30 seconds). Tried system restore, which runs for a while (up to 1 hour) and then throws an error "restore file corrupt" or something of that nature. Tried system recovery, that says something to the effect of "this system cannot be repaired automatically. Any clue? Thanks!
If you can't boot into Safe mode, try to boot into the Last Known Good Configuration (using F8).
If that also doesn't work, see How to Do a Startup Repair in Vista.
If this is the result of a infection, try first a rescue live-CD virus scanner : I like best Avira AntiVir Rescue System because it gets updated several times a day, so is always up-to-date on virus definitions.
I agree with Randolph Potter.
Also, if you're desparate to get files off of the machine, consider either: