Custom Built PC won't power on. Worked previously.

So I started building my PC about 3 weeks ago. I had some difficulties along the line, especially when it came to formatting hard drives and installing windows, but nothing major. In fact, I had my PC running completely fine, and even played about 2 hours of Cities Skylines on it. The problem happened when I installed a wifi card. After installing it, the computer would no longer boot up, not even a light on the power switch. I assumed it was the power supply, which at the time was the Corsair CX600 (there had been thunder and lighting in my area, despite using a surge protector, it seemed like the most likely reason). Of course, I could very well have fried the motherboard with static, as I don't own a wrist strap, however I did not feel a shock, nor hear anything, and I had touched the outside of my (metal) case before going in. I sent this back and used the refunded money towards a replacement PSU - the Seasonic 660W Platinum certified power supply, as I had read on here that they were the best power supply units. Just today, I plugged it all in, and the computer would not start. I unplugged it all and found that a motherboard cable wasn't plugged in (there are 2), my mistake for using a modular power supply I guess. So with that plugged it, I used the paperclip method to jump start the power supply, and it worked. So power supply is ruled out of the question. After connecting the PSU up again, the computer still won't start up, and even when using a paperclip across the 2 power switch pins on the MOBO. Is my motherboard fried? There was no smell, and no brown bits, and the metal things that stick out (can't remember the name of them) are flat, not round. So in a nutshell, it doesn't LOOK broken.

My PC build:
Intel i5 4690k
Asrock z97 pro4 (MOBO)
16GB vengeance RAM DDR3
Corsair h90 cooler
EVGA gtx 970
Seasonic Platinum 660W power supply
Samsung 850 evo 500GB
WD black 2tb
Telnet wifi card (I can find out the specific model if it helps at all)
NZXT s340

Hopefully somebody can help. I can provide pictures, additional information if needed. I spent over 1000 pounds on the parts, so I really want to get it fixed ASAP. Any help at all is appreciated.

Thanks