I have a computer with two graphics cards (nvidia). The card that the monitor is connected to has an s-video outlet. I connected the s-video cable to the graphics card and ran it to the s-video outlet on the back of the tv. When I switch on the computer I get a display on the tv right up to the point where it asks for the administrator password. After typing in the password the computer goes into windows but the tv screen is grey. I've tried adjusting the display setting but no luck. What could the problem be? Does it have to do with the fact that the computer has duel graphics cards?