My video card wont start up :[

i just put together my computer eveything seemed to be powered on such as fans and lights, the only thing that didnt have power was my video card. at first i thought it was my psu. so i end up buying another and still no change. so my friends and i chalk it up to being a faulty mobo, so i get another one, and still no change :[ im losing all hope! please someone help me!!!

my specs:
-Asus M4A77D Mobo
-Nvidia Gforce GTX 275 OC
-CPU AMD PH II X4 940 BLK 3.0G
-PSU OCZ|OCZ600MXSP 600W
-OCZ Reaper HPC Edition 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800

switched out the mobo and psu w/
-COOLER MASTER Silent Pro 700 RS-700-AMBA-D3 700W ATX12V V2.3 SLI Certified -CrossFire Ready 80 PLUS Certified Modular Active PFC Power Supply
ASUS M4A78L-M AM3/AM2+/AM2 AMD 760G HDMI Micro ATX AMD Motherboard