My dad's got a problem with this old PC, which doesn't boot properly. When he powers it up the POST screen comes on, but then moves slowly onto the "Checking for bootable CD-ROM..." etc bit, and eventually the screen just goes black and it freezes. I think it stops responding altogether as numlock etc won't work. I tried just booting from the HD etc, and turning off the CD booting option but this did nothing. However, my dad noticed that if he presses a few keys like space and enter on his keyboard repeatedly from when the power button is pressed, the computer boots normally. Any clues? It's a strange one.