I had a P4 chip in my pc, which I built using a guide from my workplace and a prescott 3.4 ghz socket 775 chip. When I left for another job my employer asked for the chip back. I replaced it with a 3.2Ghz 641 p4. The problem is that the machine wont boot. I am getting Fail messages on the motherboard. Have I bought an incompatible chip or can anyone come up with any suggestions as to what I might be doing wrong?