OK um well my friends computer died a few weeks ago so i switched the power supply in it and got it back up and working. Then we couldn't get any video from it, and so we cought a new video card, as we tried several different monitors, and they all didnt work. Now withthe new video card it is still not working, so i tested it on my known to work monitor and nothing. I removed the cmos battery, and reseated the cards, and still nothing. Whats the problem, hand how do I fix it?