My next thought would be to connect to the onboard video of the mobo and see if you get output there. That would narrow down if it's GPU or your system. Unfortunately just looked at your mobo and there's no on board.
Can you try the GPU in another rig?
So I just tried using a different GPU with no luck, so I think my GPU is okay...
I doubt the CPU could be causing this issue?
So that leaves my motherboard or power supply... Do you have anymore advice? It helps