My PC suddenly stopped working and I'm beginning to think that my gigabyte ga-81rx motherboard is to blame. I found that if I turned the power supply on, the CPU fan would spin for a couple seconds, shutdown, and the pc would not boot. If I remove the RAM, the CPU fan will continue to spin until I turn the power supply off, but the PC will still not boot. My first inclination was a bad stick of RAM was to blame, so I replaced it, but the problem persists. I have also swapped out the power supply and video card just to be sure, but they are also in working order. It's not the CPU fan since it runs fine with no memory in the board. That leaves the motherboard and processor. Anyone have an idea as to what is wrong? Many thanks in advance!

i be inclined to think its the mobo but if you can borrow a cpu of a friend or you put your cpu in a friends pc if that is possible and the cpu is fine there is noting left to try thus it will be the mobo through process of elimination i assume there is no boot beeps?

No beeps whatsoever.

You changed the Ram, PSU , Graphics card i would expect some beeps apart from if the ram was dogy but you changed that the chances of it been a burnt cpu are small but possible ( if you were having heating problems or something) so if you are unable to test that i would personally replace the motherbaord. Assunming that your speaker is connected right! also check all cards are correctly seated in slots give then a good push this can sometimes stop a PC from booting though rare, also unplug all ide cables to see if you pc then boots. In my experiance if the pc stops working suddenly like yours it's normaly the mobo is fried from the PSU going bad well has been with me from using cheap generic PSU but power surges can do the same thing. Also the cpu fan is still spinning but no boot beeps a dead give away of faulty PSU or Fried Mobo in my experiance hope this may help you