Random Shutdown During Boot

I've been having trouble with one of my machines where it will periodically shutdown during the boot process. Sometimes it happens and other times it is fine. Lately, I haven't been able to get it to fully boot at all. it seems like it shuts down at almost the same point each time.

Things I've tried: -memtest and swap out memory for new memory -try different slots for memory -remove video card and use integrated video card -remove dvd burner -reinstall OS (Windows 7) -install alternate OS (Windows XP and Ubuntu -- same issue happens)

The only thing left that I can think of would be a bad motherboard and/or CPU... Has anyone experienced any similar issues?

From serverfault DaRkMuCk

• Swap out a known good power supply.

  Check cooling on your cpu (at least see if the fan runs when you turn it on).

  Ben : +1, was just about to say check the PSU myself.

  DaRkMuCk : Fan does spin, I'll have to check the PSU

  DaRkMuCk : PSU was the problem, I just installed a replacement and it seems to be working just fine now.
  From GregD

• If you have any onboard event logging on the board, check that.

  Last time I saw something like this it turned out to be a faulty temperature sensor on the mainboard. The sensor would trip, and the OS would shut itself down. The more you tried, the shorter the period between the startup and the auto-shutdown (because the computer was getting warmer).

  Checking the onboard management showed the temperature event. Had the mainboard swapped, and all was well after that.

  From David Mackintosh