PC shutting down after 1/2 second, i7 940, Rampage II Extreme

[rhysprice73]

I have a homebuilt system with a problem, all power dies after around half a second after pressing the power button. I have tried replacing the PSU and this has not fixed the problem, I have also tried disconnecting the power and reset buttons on the case in case this was causing the problem. I have tried running the PC outside the case on a workbench using only motherboard, processor, cpu fan, and psu, this still replicated the problem. I have also tried running the aforementioned hardware without the 8 pin cpu connector and this has stopped the problem. Obviously the machine cannot run without this connector attached so the problem cannot be avoided. The issue I am having is determining whether it is my motherboard or processor at fault. I did try running the motherboard with the 8 pin auxillary power attached but without a processor attached on the advice of ASUS support and the board was able to run until I stopped it. This leads me to believe the processor is at fault however I am not sure since if there is no processor in the socket, then there is no power transfer from the motherboard and the problem could still be motherboard related. Any suggestions would help since I am out of ideas.

I did manage to make this machine run by reseating the processor and it worked fine for around 2 weeks, I only had the problem again once I disconnected the PSU mains power to replace a case fan. I now believe this brief working spell to have been a coincidence since I tried reseating the processor again and still have the problem.

My hardware is as follows:
Intel Core i7 940
ASUS Rampage II Extreme
4096MB Corsair Dominator 1866MHz DDR3
Zotac NVIDIA GeForce GTX 260
iCute 1000W PSU (Tried an OCZ 650W too)

If any other information may be relevant, feel free to ask.

 

[rhysprice73]

it appears my question hs been posted twice even though I got a flood error and was told it couldn't be posted.