116 BSOD, even after replacing graphics card and reinstalling drivers

Ok, third try

Okay, wow. My computer just flat out died. It powered off like it has the last time I mentioned, but when I press the power button, the power supply just makes a clicking sound.

Here's a video:

https://drive.google.com/file/d/0B-X...ew?usp=sharing

So... maybe it was a PSU issue after all?

I'm thinking I should buy a PSU first and then if the system starts up, great. If not, I continue by buying another motherboard/CPU?

Btw, yes, I tried clean installs and temperatures are fine. I even switched to a blower style reference card second time around which stays cool and quiet. Unfortunately it only has one PCIE x16 slot I think. I'm going to double check.

Okay there's a second PCIE slot, but there's no room since I have a Sound Blaster Z in there and the system won't even turn on now. So first order of business is PSU I assume?

Before I do anything else I'm going to test that PSU on the voltmeter again.

Oh and the motherboard (and attached USB accessories) lights up when the PSU switch is on, the little start button is on and everything. It's just that the clicking starts and the system won't boot.

Okay, what the hell. I took out the PSU to test it, and it seemed to be okay. Voltages were normal. So I plugged it back into the motherboard and now the system starts up! I'm at a loss here...

I'm going to leave it on a while and see what happens... Could it have been a short in the case or something? Because the motherboard tray is now outside of the case and all the case fans are unplugged (only CPU fan is plugged in). The case is very old and dusty (even though I use an air duster, there's still a layer of dust everywhere).

I don't see why a possible short in the case would cause a 116 TDR error over and over though?

I am at wit's end here. I put the system into a new case, a Corsair Carbide 200R. Very roomy. Made sure motherboard was nice and secure. I turn it on and several hours later, it crashes with another 116 error after almost one week without any problems with the motherboard outside of the case.

I have a week long trip which makes this frustrating to deal with. When I come back I'll try unplugging the front panel USB headers and see if that resolves it. If not, I'll try unplugging the case fans. If not, I'll try running it with the case laying flat on its side. Last scenario, I'll use the second PCIE slot, although that means I'll need a new motherboard/CPU anyway in order to fit my sound card which I need.

Any other ideas?

I was told by the tech at the store that the front panel USB 3.0 headers can sometimes cause problems with the motherboard. Has that been true in anyone else's experience too? It's strange that it would keep causing a 116 BSOD.

Or that this would happen out of nowhere. I mean at this point it's looking like the motherboard's having issues with the PCIE slot on its own, perhaps due to age (2011). It's under warranty but I don't have the time/patience to follow through on that.