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-