Yeah, have him sign up to LQ and post his errors so we can try to help him out.
Seriously though, I don't have enough information to know how to help. I'd have him boot up with his boot disk, pass root=/dev/hda1
(or whatever his actual root partition is), and then do less /var/log/message
to get the error message(s) from start up. After that we might have a better starting point.