Have you tried the video card in another computer to make sure the card is OK. Plus the PSU is a little low on power.
I know the case that you are using, you will have a tuff time finding another PSU for it.
You have been lucky to get the video card too work at all in the first place.
GIGABYTE-GA-GA-X79-UP4 i7-3930K 3.20GHz, G.Skill 32gb DDR3 2133 Quad, His HD 7850 4GB, In Win Glacier 900W, COOLER MASTER HAF 932 , 256gb SSD, Win7 Ult-64bit, 32" LED TV
GIGABYTE-GA-990FXA-UD5R, FX-8150 3.60GHz AM3+ 8-CORE, Mushkin 8gb DDR3 1600, EVGA GTX 480-OC 1.5GB, Ultra 750W PSU, IN WIN BUC 101 Mid Tower, Win 7 Pro 64bit - Play around with computer