Ok so i buildt my computer, turns on fine, but when i hook my screen to the Asus HD 6870 Graphics Card nothing shows up. I have a ASUS MB P8H67-M PRO moherboard, So the card gets Power, the fan is going, but when i hook up to the screen, nothing shows up. the thing is i have tried two cables and two screen and still it dos not work, please help me out