I have this new pc that I just built. When I press the power button the CPU heat sink fan and the HD spin for 3 secs and then shut down. Anyone have any idea whats wrong? Did I hook up the power button wrong? I tried differnt varations.
Sounds like a power problem (or lack of), what is the rating of your PSU, including the AMPS of the 12+V and 5+V rails? This problem can also occur if the CPU is dead or a MB fault. Try swapping out the RAM and graphics for known working models to narrow down the cause.
I had this problem and it drove me nuts!!! What I found was that my thermal probe for my front display was shorting or something on my HS or cpu..... (sounds bad I know). When I moved the thermal strip or removed it completely the computer booted just fine. Now you may not have a thermal probe.... so just check for something that could be shorting somewere.
Could also be the BIOS not detecting the fans spinning or temps the way it wants and shuts down. Make sure the cpu fan is connecter to the cpu fan header and not the case fan header or something. A bios reset may also help.