I built a new PC late last year and it has run fine till now. (spec as listed in my setup at the side)
Then this morning, was checking email when it powered down, the blue power light went out on the case and it went silent (though screen and everything else in the room remained powered up).
Five seconds later, it powered up again and rebooted itself without me doing anything.
I checked that the power line was plugged properly into the PSU at the back and it seemed to be.
It went past the BIOS screen, asked whether to start windows normally or not (I said normally), carried on for ten or so seconds and powered down.
Five seconds later, it repeated the process.
Powered down and rebooted itself four times,
I took the side off the case with a view to seeing what was going on - not that I know what to look for.
Anyway, it hasn't done it in the half hour since, with the side still off the case - I don't know if that's coincidence or relevant.
I was particularly baffled that it went dead, then rebooted itself five seconds later without me doing anything
Can anyone suggest where to start looking or how to rectify whatever it is pse?
I don't have any spare bits to swap in, and know very little about the workings.