PC turns on then off immediately

[Revixe06]

I decided to upgrade and pick up a GTX 980ti for Christmas. After installing the new card, my PC would turn on and power off immediately after; however, after trying a couple of times, it would eventually stay on until it was turned off or put into sleep mode (wouldn't wake). It has now reached the point where it will only power on briefly, flash the "00" error code, then shut itself off. I have tried everything I could possibly think of, and I haven't had any luck yet. Hope you guys can lend me a hand. Thanks in advance!

I have tried the following:
Tried with previous video card
Tried with only mobo and cpu
Tried alternating RAM and different RAM entirely
Tried resetting cmos battery
Tried reseating cpu and redone wiring
Tried replacing the psu
Tried different oulets/power cable
No sign of bent pins, loose screws, or damaged mobo capacitors

Specs:
Intel Core i7-4790k 4.0GHz Quad Core Processor
Asus Maximus VII Hero ATX LGA1150 Motherboard
Corsair Vengeance 8GB (2 X 4GB) DDR3 Memory
Asus GeForce GTX 980ti Strix 6GB Video Card
Corsair RM850 850W Power Supply

EDIT: Built this rig over the summer and it has worked like a charm until now.

 

[N3rdR4ge]

you could try disassembling everything and reassembling it, outside of the case, on a desk. could be a short from metal on the case touching metal on the mobo, possibly a standoff (pins lifting mobo from case that accept screws).

otherwise you already did all the diagnostics to point to a faulty mobo.