X51 R! new case and PSU. Power Relay Source issue????

I swapped my old x51 R1 into a new case. I added an old 400W PSU from a friend and everything seems to be working fine. However I can't get anything from my GPU. Running HDMI straight from my board I can access my computer and I keep getting a "Power Source Relay Issue." upon start up. I press F1 to bypass. I installed the most recent driver for the GTX 660 and this worked for a bit until I turned it off again. It's as if the computer can't decide if it should use my board or GPU. Any advice or similar problem?

New to computers btw :)
You should be plugging your video cable into your GPU. You might need to go into your bios and set priority to your external video instead of onboard/integrated.
Yes that is the issue....nothing from the GPU. It was suggested by a friend that I enter the bios and disable my onboard graphics. Not sure how to do that exactly...