I'll let others work with you on the kernel version .... (which we'll assume is OK and a true CentOS install).
I would put up a console on the local KVM port to capture the last set of messages before the system hangs -- which might help isolate the problem.
From what we've seen so far, it sounds like you might
have a hardware problem. The things that I would check are:
- power supply (aka losing voltage) - all the system fans (aka thermal shutdown) - memory (run memtest86+ overnight [or longer])
If not that (and still a hardware problem), it is a lot more subtle and will be "fun" to diagnose ....
Hope this helps (a little) ...
-rak-