System shuts down for no reason

Weird situation. I build a computer for a friend. It ran with no problems for over a month. Now, at my friend's house, the computer will shut down after running for only a few seconds. If you touch the case, it'll start up again for another few seconds. It makes a loud "CLICK" sound when it turns off. Tried multiple outlets. Tried a different power supply. Took it to my house, and it worked perfectly fine all night. I checked for loose screws, found none, so I know it's probably not a short, eventhough I've got a feeling that it is. Anyone have any ideas of what it could be?

Admend that. I took it back to my house, and it's doing it here too. Weird that it didn't do it before. Any suggestions?

 

Shut downs are usually heat related. If it happens a few seconds after startup, it sounds like maybe the CPU fan isn't even starting and the computer shuts off to save the chip.
Open up a side of the case, turn the computer on and watch what happens.

 

The fan is spinning up fine. I spoke to the techs at the place I got it from, and they're saying it's either not properly applied thermal grease, or a bios issue. I wish I can get it to run long enough to flash the bios...

 

It sounds like a short to me. Some PSUs will automatically shut down on a short condition and then reset automatically once the short condition is resolved, hence, the big click sound you describe. Have you checked to see if the Mobo is touching the case? (on the back of the board). You may need to install small "standoffs" to the mobo before installing it in the case. The mobo manufacturer usually includes a set of these in their hardware bag of screws. I have had similar problems on a couple of builds and this was the problem.

 

I had a problem with an Abit mobo that had a mounting hole in a standard place where a stand off would go on the case but was never meant to have a standoff there. It worked for a while then it stopped and boy what a hassle trying to diagnose. If it where not for a random post on a site I happened upon I would have probably RMAed the thing and had the same problem when I got the new one. I since found out that Abit knew of the problem but kept quiet and refused to acknowledge they goofed.

What I did learn is Abit is not the only company that has done this (It has to do with the standardization of the board versus what the engineers design onto it). I also found out that by examining the board carefully you can determine if a hole is meant to have a screw in the first place. Since board screws are nearly always also grounds, if the hole doesn't have star shaped or ring shaped solder around it, it may not support a standoff or screw. In my case the Abit board did not have any solder around that hole but did on all the rest. Once I pulled the board and remove that standoff the problems went away. Abit AN8 32X SLI, in case your wondering.