I recently installed an NF4SK8AA, WinFast systemboard in my son's computer, which has an AMD 64, socket 939, processor. At first, when you turned the pc on, it beeped once and the cpu fan would spin for about 10 seconds and then stop. I removed the heatsink/fan and cpu several times and replaced the thermal grease and eventually, it stopped beeping and seems to be running normally. All fans on the pc are running and there is power to the hard drive. However, now there is no video. All cards have been removed and everything disconnected, including hard drive, floppy and cd-drives. All memory except for one chip has been removed, and still no video. I tried to swap out the GEForce card with a plain-jane video card and still no luck. Cleared the CMOS, no luck. Switched slots for the PCI Express video card, no luck. The monitor is a working monitor and was verified. Even used a different monitor just to be sure, but still no luck... now I'm at a loss.... what could be causing this?