PC Problem

I went back to my hometown this weekend, bring along my PC...
and the weird thing was, it always had problems when I bring it back to my hometown.
My PC will auto-restart or hang without any reason (not that I know of).
I've tried to fix it, but it was not successful... Those problems doesn't occur when I was in Bkt Beruang... I'm not sure whether any of the hardware is damage. I've tried every possible method to find out the cause. I've exchanged my RAMs and display card with my housemate, unplug the CDRom drives, re-configure my BIOS settings, Windows Settings, Display Driver, etc...
But nothing seems to help... The problem is a type that goes on and off without any warning. So I may end up having my whole report that I was doing the whole day, gone right in front of my eyes.

Really fed up with this problem... Can anyone there help ???