computer won't turn on when cold

[StarTiger]

I just put together a new system and it run fine except when you go to turn it on on a cool morning. if it's below about 71 F, when you hit the powerbutton on the front, it turns on for about half a second and then shuts off. you have to unplug it and plug it back in again for it to do anything after that.

once the room warms up to 71F, you puch the power button and it runs fine.

any idea's what's wrong?

thank you for your input.

[mdwatts]

Turn down the air conditioning? ;)

What hardware do you have? Case/power supply?

We've had problems posted here on overheating, but never have I seen one as yours.

Is this a system you built yourself? Checked all the internal connections? Bios settings?

[EnigmaOne]

Hmmmm....it actually sounds like an issue with the power_good signal feedback to the power supply.

Open it up and make sure the motherboard isn't shorting against the cabinet at all--not even close. Also insure that the motherboard isn't in a flexed condition.
If you have metal M/B mounting stand-offs, insulate them.
Check all wiring from the P/S to the motherboard thoroughly.
Check the wiring to the front panel power switch.
Check the length of the screws used to mount the hard drives.
Make sure there isn't a short or close short between the hard drive electronics and/or wiring and the chassis.

With it open, fire it up and observe the processor fan. If it seems a bit slow or "draggy" in startup rotations, replace it.

Have the memory modules tested.

If you just built the system from new components, and you can't find anything wrong inside the cabinet, RMA and exchange the power supply (first) then the motherboard.