PC won't boot unless GPU unplugged/not seated

Anxiety5k

Honorable
Mar 8, 2012
9
0
10,510
So last night I booted my PC into sleep mode (as usual) and went to sleep. Came home from work this evening and PC wouldn't boot up. Turned it off and back on, and every time I hit the power button, the motherboard light appears and it instantly turns off. HOWEVER, this wasn't my first rodeo, so I start removing components. I got the GPU and took it out.. instantly. The PC booted up, ran smoothly. I put the GPU back in.. nothing, won't boot:

SETUP:

Gigabyte Aorus K5 Motherboard
EVGA GTX 1080
i7-7700k
1000w CM PSU
16gig Corsair DDR4
240gig Intel SSD (Boot drive)
1TB Seagate standard HDD


Things I have tried:

1.) Removed all components except CPU (booted)
2.) Added RAM (worked/booted)
3.) Added GFX card (wouldn't boot)


Plugged HDMI cable into motherboard[removed GFX card] (hence how I'm here) and it boots fine.

Possible key notes?

If I remove the PCI cables from the PSU and the GPU is still seated.. the PC will boot fine.

If I leave the PCI cables plugged into PSU and unplug them from the GPU.. PC still boots fine.

If I plug the GPU up normally (PCI cables into PSU and GPU) PC will NOT boot.



I have a friend coming over with another GPU to test. However I don't have another PC to test my PSU.. no a PSU to test on current PC.


Thank You,
keaton056