Greetings all,

OK, long story short the PC cut out suddenly last night, and would not turn back on.

I disconnected everything, leaving only the CPU (& fan) and 24-pin and 8-pin power connectors connected. It would still not turn on.

If I unplugged the 8-pin connector, the PC would turn on and spin the CPU fan, but once I re-connected the 8-pin power it would no longer turn on again.

Here's what I know:

I have two motherboards to test with, both ASUS, a P8P67 LE and a P8H67-M Evo.

The H67 won't turn on at all with the 8-pin power connected.
The LE will turn on with it connected, but gives no picture of any kind, no HDD activity and a POST card does not give any numerical error codes, just lighting the LEDS indicating power (5v, 12v etc). It will do nothing for a few seconds, before rebooting itself.

It's not a short in the case, as I've made these tests outside of the case.

I'm thinking the PSU is faulty, but can't also help thinking that the H67 mobo is faulty and maybe the CPU is dead (which would explain why the LE works fine but won't boot).

Any thoughts?

On another note, would someone be able to test the CPU (i7 2600K) as working for me? I don't know anyone with an 1155 motherboard, and once I know if it's working or not I intend to shove it on eBay and go back to using AMD.

I'd suggest of the same PSU has issues on two different motherboards that would be my first guess.

My Dad's PSU went once and took the gfx card and CPU out with it too though so it entirely possible some other compenent went up too.

I had a PSU become dangerously unstable a couple of years ago and it took the motherboard out as well. I was lucky as it was only the mobo that was damaged. I had to pay for a new one, but at least I didn't have to buy any more replacement components.

If you don't have a PSU tester, then I would hope that you have access to a multimeter. Short the main 24 pin connector GREEN wire to any of the black ground wires and measure the voltages on each rail.

Stick a fan or two onto the PSU and see what happens- in my case it was the 12V rail that was knackered, but if you have something that runs of the 5V rail, give that a try.

Update:

PSU was faulty, and it had taken out both the MoBo and the CPU. SandyBridge has been a complete nightmare for me, tempted to give up on the PC for gaming and just stick with the PS3 TBH.