i have a problem with my computer when i shut down the cumputer the cpu fans and case fans are still running along with the harddrive led is blinking and the fan on my vid card is still running i have restarted my computer when fans are still running and my computer boots and screen is garbled let computer sit for 3 mins boots normal i have un plugged from the power strip and fans quite running i have also unplugged mother boards and everything stops plug power back into motherboard and system fans start running again. i believ my mother board is shot could this be the cause of a VIRUS on my motherboards bios. my computer specs are as fallows

motherboard asus a7n9x deluxe
cpu amd athlon xp 2000 133 buss speed
ram 512 corsair pc 133
video card agp pro 8x ati radeon 9700 pro
hard drive is western digital 40 gb
cd rw is a btc 24x

mother board is an a7n8x deluxe type O sorry