Gigabyte Z97X-UD3H-BK won't power on

[NukeFromOrbit]

Well today I opened up my PC (which has been working well for at least 3 years) to replace a 120mm fan that was in the process of dying and add a new M.2 SSD which I had bought. After everything was all set and done I go to boot up my computer and nothing happens. After a long process of troubleshooting now have the motherboard on my desk (it's plastic so it should be non-conductive) with nothing but two sticks of RAM, the CPU and CPU cooler, and the PSU connected to the board by the 2x12 and 2x4 power connectors. This should be the minimum that is required for the board to POST. All SATA drives, the M.2 drive, and the video card have been removed.

Trying to short the pins for the PWR switch fails to cause any reaction. No fans or lights anywhere. I have tested the power supply independently with a cheap tester and it seems to be functioning fine. I have tried a second power supply and still nothing happens.

I was sweating a bit working on the PC earlier since it was a hot day and it's possible some sweat landed on the board. Is it possible that could have killed it somehow? I'm usually quite careful about preventing static discharge but I suppose that's always a possibility.

So does anybody have any ideas of what to do next besides for being extremely frustrated at my luck? I've invested a lot in the PC over the years and it would be a shame to have to start from square one.

Any and all advice is appreciated. Thank you.

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

How old is the PSU?

 

[NukeFromOrbit]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

How old is the PSU?

Hi Lutfij, here are the specs of the PC when it was all in one piece.

CPU - Intel I7 4790k
Motherboard - Gigabyte GA-Z97X-UD3H-BK Black Edition Rev 1.1
RAM - 2x 8GB GSkill DDR3-2400
SSD/HDD - Kingston 480GB SATA SSD, Western Digital 1TB HDD, Western Digital Velociraptor 300GB HDD
GPU: ASUS GTX 970
PSU: 850w Antec Truepower Quatro
Chassis: It's a rather old case from NZXT and I can't see any obvious name
OS: Window 7 Ultimate

The PSU is rather old (at least 5 years) and from a previous build. Yet everything was green on the PSU tester. In an effort to rule out the PSU as the culprit I currently have the motherboard connected to a Rosewell 500W PSU which was leftover from a recent project and hasn't seen much use. That one also looks good according to the PSU tester.

I fear I may have shorted out the motherboard somehow.

In retrospect I should have selected "discussion" instead of "question" for the type of thread. Is there any way to change that?

 

[NukeFromOrbit]

Been messing with it for the past day and still no luck. I'm guessing the motherboard is at fault but is there any way I can rule out the CPU before I go and order a new one?

I'll likely buy a new PSU for it as well.