I have a Radeon 4890 series card that seats poorly on an asus m4A79 deluxe motherboard. My computer has been fully functional for 2-3 years now, but after shifting it around on my desk the other day, I stopped receiving any video output at all.
I cleaned the entire machine with an compressed air electronics cleaner, and re-set the card. Still no picture. After that i tested my moniter, changed HDMI cables (though I'm using a DVI-d to HDMI adapter that I'm in the process of replacing), tried using every combination on my moniter and computer, and trying a friend's graphics card without any luck. Any other ideas? Is my motherboard fried? The card still receives power, and the fans all spin. I don't have access to a smaller card to try the other GPU ports on the motherboard, to see if they work.