The computer's mobo is kinda old but I don't think it should matter. I have tried connecting the computer with DVI, VGA, build-in VGA cables, still no signal. But the computer was working at my friend's house. I have just removed the HDD and put mine it. Help?
Hard drive or no hard drive, you should see something on the display unless the computer isn't passing POST, or something is wrong with the video adapter or anything along the signal path. Try a different monitor and cable. If you still see no video, try a different video card. If you still get nothing, remove all removable parts except the processor/fan, one stick of memory and the video card. If you still see nothing, swap DIMMs. If still nothing, then it is probably the motherboard.