Well I "upgraded" the CPU in my son's computer today or attempted to anyway.
He has a Dell Optiplex 755 Desktop. Before starting I upgraded the BIOS. That went fine. PC rebooted normally and all seemed well. Took out the old CPU (Intel Core2 Duo E8400 @ 3.00GHz 1333) and replaced it with a Intel Core 2 Quad Q9650 Processor 3.0 GHz 12 MB Cache Socket LGA775 which was supposed to work based on the research I did on the Internet. Hooked everything back up and no boot. No lights, no BIOS beep, no nothing. The fans start up for a few seconds then it shuts off.; A few seconds later it does the same thing and keeps doing it until the power cord is disconnected.
So I put the old CPU back in and it does the same thing.
Can't remember the part number of the motherboard but I don't really know what to try next? I made sure all of the cards, RAM etc were seated and all.
Only thing I can imagine is that the new CPU was NOT compatible and somehow damaged the motherboard which is why the old CPU won't work either. Tried reinstalling both very carefully a couple of times with the same results.
Any thoughts or suggestions?