|To check how the system is stopping - whether via BSOD or other issue can be difficult. Sometimes you can see the brief flash of a Blue Screen w/ white letters & numbers while it is turning off.|
Also, if you get into the system with UBCD, look for minidmps (BSOD crash dump files) in the location C:\Windows\Minidump , you then can copy these off the system to a flash drive etc for crash dump analyzing with Windows Debugger (WinDBG).
How to read the small memory dump files that Windows creates for debugging:
Also - check your motherboard for bad capicitors: http://en.wikipedia.org/wiki/Capaci...
MOOOOooove! OH and you're welcome!