I had been having a problem for a while with my CPU overheating. Having built the computer maybe 3 years ago, I thought it might be due to have the thermal paste reapplied. So I got some thermal paste and thermal paste remover, reapplied to my CPU and heat sink. When I plugged the computer back in, and switched the power on, the only response I got was really strange. The computer would not power up. But the fans would all pulse over about a 3 second cycle, along with the LED lights.
I decided that I must have done something to screw up the CPU. Its an AMD Athlon and I know they are delicate, so maybe I accidentally damaged it while installing the heat sink, or something else along those lines. I procured another CPU off from eBay. Installed it. Exact same problem.
So previously I was sure I had a CPU problem. But now... could I have really screwed up the CPU installation twice? Could I have bought a bad CPU? Maybe I did something to the mobo without realizing? Its a strange symptom so I don't know what to make of it.