Trouble determining which part is faulty on 3 year old PC

[vElectrixx]

I was doing some casual web browsing when suddenly my computer shut down. Not like a full windows shutdown or blue screen, as in the screen went black and the computer was off. I tried turning the computer back on, but it showed no signs of life. The only two things that were on were the motherboard's SB_PWR light (green), and the light indicating the ethernet port is being used. No case fans, nothing.

First I thought it was the PSU. I attempted the jumpstart/paperclip test, and its fan turned on no problem. Huh. Must be the motherboard.

I took out my RAM, GPU, and sound card. I pressed the power button once every part was removed. Computer was on for a second then turned off. I pressed the power button again to see if that repeats, no response. I press it one more time and it turns on and stays on. Could it potentially be the CPU? Or is it the motherboard? I'm leaning more towards the latter, but I'm not confident at all.

Here's a list of the specs.

Also I'm willing to do any other tests to help determine what's wrong.

 

[Shektron]

Do a memtest86 to check for RAM errors, but it doesn't look like a RAM fault IMO. Still, do a few passes of memtest86.

There's a lot of things that could be wrong here. CPU, motherboard, PSU, etc. And yes, the PSU could still be faulty - the paperclip test is not a sure-shot way of testing whether the PSU is bad or not.

 

[vElectrixx]

Do a memtest86 to check for RAM errors, but it doesn't look like a RAM fault IMO. Still, do a few passes of memtest86.

There's a lot of things that could be wrong here. CPU, motherboard, PSU, etc. And yes, the PSU could still be faulty - the paperclip test is not a sure-shot way of testing whether the PSU is bad or not.

Even though the computer's on, nothing is displayed. I plugged my monitor's dual link DVI cable back into the motherboard and put a single stick of RAM back in, and nothing displays even though the computer is on (all case fans start spinning is my indicator). Just to try again, I reseated my GPU back onto the motherboard. Now it's just like my original scenario of the computer not turning on at all.

Looks like memtest86 is out of the window unless I can convince a friend to let me borrow his computer.

*I checked to see how computer turns on again, and with a single press, it turned on, shut down a second later, and after a couple seconds it turns back on again and stays on.

 

[smorizio]

start with a known good power supply. I had a unit after 6 years died..the power good on my asus mb was on fine but a leg had failed on the unit. (eps cable side). new unit power my rig back up without any issues.

 

[Shektron]

Yep, my next best guess would be a PSU issue as well. Even though you have a good unit there, there's still always the possibility of a dying/dead PSU, and your symptoms are quite indicative of a PSU going bad.