I have an HP pavilion with a q9650 cpu in it. I bought a Xeon 5640 to drop in after a couple of mods (removed plastic parts around cpu so it would fit, etc). I put in the Xeon and it started. I had no picture on my monitor so I was making sure it was plugged in everywhere correctly when I suddenly heard my heatsink fan go really fast, there was a "pop" sound so I quickly hit the power button on the computer to shut it off. I tried to restart and nothing. The fans twitch when I first hit the power button then dead. The tower fan and power fan both turn on if I unplug the 4 pin power supply to the cpu. I have tried resetting the CMOS, putting in the old CPU, which worked perfectly find before this and I get the same results. I also checked to make sure I didn't bend any pins and I a couple of them around the edge didn't seem to be lining up exactly when looking at them with a magnifying glass so I very gently pushed them back into place with a pin, still wont start/post. I'm not sure what else to do at this point, non of the posts anywhere describe my situation, even though similar, it's not the same issues. Recently installed in my computer before the xeon was put in, power supply and video card, both of which were working fine for a couple of months before this issue.