PC powers off after 8 seconds - remove CPU chip and it stays up

[billindedham]

This is a HP Media Center PC m7000. I hit the power button and it starts up but shuts down after 8 seconds. I tried a different power supply but it did the same thing. I removed the motherboard and disconnected all cables except for the P1, the power switch connector and the 12V supply to the motherboard. When the 12V was plugged in and I applied power, the CPU fan barely moves and the supply shuts down after 8 seconds. I removed the CPU from the socket and powered the MB up with the 12V applied and the CPU fan runs quickly and the unit stays up. So now I either have a bad socket for the CPU or a bad CPU. Any way to determine if I have a bad CPU chip before buying a new one?

 

[Tmagic650]

Is the CPU heatsink properly installed with thermal compound between the CPU and the heatsink? Do you have the CPU fan properly connected to the motherboard fan header?

 

[billindedham]

Yes to both questions. A friend of mine is going to bring home a spare motherboard that I can try the CPU on. My guess is the CPU but I won't know for sure. By the way, assuming it's the CPU, where do I get that thermal compound if I replace the chip?

 

[Tmagic650]

Radio Shack or Best Buy might have some thermal compound. Be sure to clean off the old compound off both the CPU and heatsink with rubbing alcohol before you apply just a small amount to the CPU surface, and mount the heatsink