I just finished putting a computer together out of parts I got on eBay. I then turned it on and it powered up for 2 seconds and then shut down. Tried it again and again and the same thing kept happening. Started to remove things piece by piece but nothing made a difference until I finally just removed the CPU and then the motherboard stayed on. Does this mean that the cpu is bad. I was reading from another message here and someone had said that it could be that the fan isn't strong enough and therefore the motherboard is shutting down as to protect the cpu from overheating. Any ideas, bad cpu, weak fan?

Have you tried clear the CMOS? Remove the motherboard battery for about a minute, with all power off and unplugged from the wall. Then put the battery back in and start up the computer.

Clearing the CMOS can usually be done with a jumper but using the battery method can require the battery to be out for many hours. I've seen this to be the case many times in my store anyways. The PSU would be culprit if the mother board didn't work with out the CPU but this is not the case so I'm leaning toward the jumper settings (and/or the CMOS setting). borelli35

thanks for the help, cleared the cmos for about a minute with the battery out and then turned on and it stayed on. But then I ended up getting a constant beep from the bios, turns out the memory was bad too.