cause the problems you describe.
My computer turns on but the monitor will NOT turn on. The keyboard flashes randomly and the harddrive does NOT turn on. But if i unplug it from the MB it will turn on with just power from the power supply. The green light is lite on the mother board and the fans are working. I Im thinking its the motherboard or its a virus.
I tried taking out the video card and puting it directly to the MB, still didnt work.
My computer is a 1.8 p4 cpu with a intel desktop board, 512 ddr, and 256 gforge video card, and 160 gig harddrive