On 6 Feb, 09:37, "Dave Plowman (News)" wrote:
I've got a home assembled PC based around an Asus motherboard. Which shuts
off at random. Not a controlled shut down - it just dies. Thinking PS
problems I've replaced it. Same thing. Sometimes it will boot up ok and
continue for as long as I want. Sometimes it switches off half way through
the boot sequence - but never at the same time. Any guesses? I've got AVG
free installed and that shuts it down after doing its tests. That sequence
always works ok.

The electrolytic capacitors on the motherboard can go. You can spot
the knackered ones as the metallic top rises up in a domed fashion.
You can change these knackered caps to repair, but watch how much heat
you apply to the board as you can easily lift tracks/pads and ruin it.

If it was something overheating it would more likely crash than switch
itself off,. Same goes for memory faults.