Here is the issue: I tried to fixed my friend's computer problem because his PC when start is on (has both lights on ie hard disk light and pc power), the fan is working, the motherboard light is on but nothing is coming up on the screen. So I think it is power supply issue but I tested the hard disk so I tried to use my hard disk to his pc and unplug his harddisk but still the same thing so I told him to get back to the pc shop and ask them what the issue or maybe invected by virus. SO I put back my hard disk to my pc and plug all the connection but NOW, my pc showing no signal to the lcd monitor so I check all connections and looks alright but this pc keep rebooting all the times. The hard disk lights, cd rom light looks working and got blinking light but after around 15-20seconds keep rebooting with NO SIGNAL AT ALL showing to my lcd monitor. I check the video card but looks ok Do you think I've invected by virus as well or because my harddisk doesn't recognise the motherboard anymore or what? Anything that I should check? Please help. My PC configuration using Win XP, 1.8ghz, 128 video car, 256ram, gigabyte motherboard and 60gb hard disk.