AMD Phenom II X4 965 Black Edition Deneb 3.4GHz
G.SKILL Trident 4GB (2 x 2GB) 240-Pin DDR3
MSI NF750-G55 AM3 NVIDIA nForce 750a SLI HDMI ATX AMD
Western Digital Caviar Black WD1001FALS 1TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5
Palit NE3X262SFHD94 GeForce GTX 260 896MB 448-bit GDDR3 PCI Express 2.0 x16
CORSAIR CMPSU-750TX 750W ATX12V / EPS12V SLI Ready CrossFire Ready 80
purchased within the last week.
(FYI i chose Asus as the sub-category, because MSI was not an option)
I put together the system and everything ran fine for about an hour or two, then the system just shut down. All attempts to re-boot the system simply caused a 1 to 2 second power up and immediate shutdown. I tried slowly removing 1 piece of hardware at a time to see where the problem might be, and in the end with only the 24 pin socket power cable connected to the motherboard, and the sw power cable (for the push button turn on) it was still doing this. So my roommate who is a hardware tech, said he believed that it was probably a bad motherboard. I purchased everything from new egg and a new motherboard is being overnighted and should arrive tomorrow morning.
I've read a few things, (on this very informative and wonderful website of yours) and one of the original concerns my roommate and I had had, was that the 8 pin eps12v cable that my power supply has *which divides into 2 4 pin connectors* and that I had put the wrong 4 pin into the motherboard. However, I read elsewhere here, that those 2 4 pins are interchangeable.
So now I'm sitting here waiting for a new mobo to arrive, and just curious if anyone here would be so kind as to provide any further suggestions about what might be the issue, or anything I should look for/test.
When you do get the new mobo, be sure to set your RAM voltages and timings to the manufacturer's specification. Also, have your friend test the PSU just to be sure that there isn't a problem in it. The PSU is a known brand, and the output is sufficient, but test it to ensure that wasn't causing the failure.
By same thing do you mean that it worked for 1-2 hours, then shut down; 1-2 second power cycle, then shut down; or both problems again?
Have you verified the temperatures of the CPU? An overheating CPU can cause the system to shut down and if you were to immediately turn on the system again, it would shut back down because the heat is still to high.
On the other hand, the PSU is still worth exploring. If you have another computer lying around, you could do a swap to check the PSU in your new build to see if the old computer experiences this problem.