Newly built system randomly doesn't post?

[creemerica]

I recently built a computer for my friend, but for some reason it will randomly not post sometimes. No beep, no video signal, no nothing. Just the fans spinning. But, you turn it off, wait a little bit, turn it back on and it posts. What is causing this? Here is the component list:






GIGABYTE GA-P55A-UD3
EVGA 01G-P3-1366-TR GeForce GTX 460 SE (Fermi)
CORSAIR CMPSU-750TX 750W ATX12V
Intel Core i7-870 Lynnfield 2.93GHz
G.SKILL 6GB 1333 (PC3 10666) Triple Channel Kit Desktop Memory Model F3-10666CL9T-6GBNQ
Western Digital Caviar Black WD6401AALS 640GB

Any help would be greatly appreciated. Thanks!

 

[Emerald]

does only happen when you reboot?

It could be a heat issue.

have you checked the memory?

it could also happen when the motherboard does not get feedback from the CPU fan

 

[creemerica]

does only happen when you reboot?

It could be a heat issue.

have you checked the memory?

it could also happen when the motherboard does not get feedback from the CPU fan

It happens after he turns the computer off for awhile, and then turns it back on. We checked the memory, it all seems to be working fine, all the timings and voltages are right in the bios, and it passed a memtest. Also, I dont think it is a heat issue, the BIOS says the CPU is running at 21 C, and the case seems to stay extremely cool.

 

[mdd1963]

The sensor in the cpu heat sink is at 21C, not the cpu itself...; I'd suspect the sink has insufficient contact with the cpu with that sort of low reading...

 

[creemerica]

The sensor in the cpu heat sink is at 21C, not the cpu itself...; I'd suspect the sink has insufficient contact with the cpu with that sort of low reading...

Im not really sure how to get a more accurate reading then or how to increase the contact between the CPU and the heatsink.

 

[stevediaman]

get a camera and take a picture of the bios screen when it does not post and post it here.

Also try with a different video card, and if your board has onboard video, try it with that only.

Strip the computer down also to bare minimum

 

[creemerica]

get a camera and take a picture of the bios screen when it does not post and post it here.

Also try with a different video card, and if your board has onboard video, try it with that only.

Strip the computer down also to bare minimum

You cant get to the bios when it doesnt POST. It will work fine for a week, and then it will randomly decide not to post.