Corsair PSU only works out of the case

[beeboop]

I having issues with my computer's PSU. I purchased this computer from Newegg a couple of months ago.
Last month the original PSU died, I turned the computer off and when I went to turn it back on it would not do anything. I purchased a replacement PSU, a cheap off-model brand. That one Died after two weeks.

I assumed it was the model of the PSU so the next one I purchased was a Corsair CX 500M. It worked great for a while, but now after only two weeks it did the same thing, I shut the computer down yesterday and when I tried to turn it back on it would not power on or beep. This morning I opened the case and pulled the PSU out and it worked. So I installed back in the case only to have it refuse to power on at all. I have it working now, but only with the case open and the PSU loose inside of it; it's pushed back from the wall of the case and the screws aren't in it.

Obviously I can't use my computer like this. Does anyone have any idea what could be wrong? Is it the case or the computer? Another faulty PSU? I'm lost

 

[HiTechObsessed]

What kind of temperatures are you getting on your CPU/GPU? And can you list out the specs of your computer? It sounds like something is shorting on the motherboard, causing the protection in the PSU to shut-off, but I don't know.

 

[techgeek]

That sounds like an odd grounding problem. Are the standoffs under the motherboard metal? Ideally one or more of the screws that hold the motherboard on the standoffs will be connected to the ground plane on the motherboard. The standoffs should be metal and therefore make an electrical connection to the case which in turn if the PSU is mounted have a common ground with the PSU chassis. It seems to me that something isn't right with the way your motherboard is mounted in the case. Check to make sure the standoffs are metal and make sure that all the screws holding the motherboard in the case are there.

The other thing is maybe you have a wall socket wired incorrectly. Have you tried powering your computer from another wall socket?

 

[beeboop]

What kind of temperatures are you getting on your CPU/GPU? And can you list out the specs of your computer? It sounds like something is shorting on the motherboard, causing the protection in the PSU to shut-off, but I don't know.

I haven't been measuring the temps because it doesn't seem to overheat, it just works normally, powers down then won't power up again. I downloaded coretemp and it says my computer is running at 19 C

I'm running AMD FX-6100 3.3GHz with 6 cores, 16MB Ram with a 1TB WD Blue Harddrive. My graphics card is NVIDIA Geforce GT 640 2GB and I added a Kingston SSD as my primary boot drive.