Putting this in the run dialog may get you somewhere:
cmd /k systeminfo | @find "Original Install Date:"
This won't work properly if the OS was reloaded from an old image. I'd also check the creation date on the WINDOWS folder, which may also be off. I can't really think of any solid ways to get an install date unless I knew what method was used to install it (image restoration, clean from disc, etc.)
I wouldn't know why it would stop booting though, or why they would need to reinstall, unless they replaced the motherboard, which would prompt such a thing. Kinda sounds to me like he wasn't properly grounded when he tightened it with a (possibly) magnetic screwdriver and cooked part of the mobo. That would most definitely account for issues in booting.
Edited by Riker, 10 June 2010 - 11:44 PM.