Getting no display on monitor, HELP

Been having CTReboot's for awhile. Thought it was a software issue for some time. Finally decided to check inside case and the fans on my Asus 9800 Pro 256MB were not spinning. That may be why it has been crashing all this time. I decided to take out my card and remove the fans and heatsink to inspect the card. I did not see any damage to the card, so i put the heatsink and fans back on and put the card back on the motherboard. I plugged power to card and turned computer on. I now get no display to the monitor. The video card is getting warm, but I get no display. The computer worked that morning, but now nothing since I took it out. Also, I don't know if computer is in BIOS or if it has gotten to Windows, but my mouse's optical light is not on. None of the USB ports are working. Thanks for any help.