Not getting any video signal in Windows XP. Can tell that windows is booting from windows wave file playing upon bootup. Had on-board video, so purchased new video card (GeForce 8600 PCIe). Problem seemed to be fixed when I plugged in new card, video feed worked great, graphics looked awesome; but it only worked for about 4 days, and now computer is doing the same thing...giving me "no signal" on my monitor upon booting up. Wondering if its a motherboard problem or if there may be some other issue?