I just bought and replaced the CPU fan on one of our office computers because the old fan would occassionally get very noisy. I took of the old fan (for a 370 socket) latched on the new fan and plugged it in. When I powered up the computer the fan worked and the HD light came on temporarily but that was it no video! I connected another monitor that I know works and still the same thing. In an attempt to test the video I plugged in a keyboard and started up the computer. The lights on the keyboard blinked twice as usual but the number lock light never came on even though I left it on for a couple of minutes and the monitor was still blank. Could it be that something happened to the CPU in the fan replacement process? I was careful doing the replacement although I did have to push down a bit hard on the bar that comes through the fan to get it down far enough to latch. Is there any way I can determine if its the CPU, RAM, Mobo or something else without buying more RAM or another CPU an testing?