This on my friend's computer that I'm helping with. He bought a barebones kit with an athlon xp 3200+ and an Asus motherboard. The chip was running hot, like 60*C, so we decided to change the heatsink before we went any further. He bought a heatsink, and the thing ended up being a monster, and required backplate braces for behind the motherboard. So, we take the motherboard out and install the backing plate (correctly) and then button everything up and turn on the computer. Doesn't post. We have no beeps, nothing. monitor just says the check the signal cable (same message without a cable hooked up). Any ideas one what could have caused this? We have changed out the RAM, video card, and power supply. Also tried unhooking everything except the MB from the power supply. Any suggestions would help a lot.