Random shut down.....

[Tyler22]

OK I built a computer for my girlfriend and it keeps randomly shuting down. The power supply is brand new. Everything else is used. It will shut down if you tap its case really lightly or sometimes you don't even have to touch it, it just shuts off. Any idea on what it could be? Thanks alot.

 

[TWills]

1. Check all cables carefully. Wiggle them all and see if there's one that's causing trouble. If there is, electrical tape it in place!
2. Check the power saving features on the mobo. Shut them all off, as they tend to cause problems here and there...
3. Reseat the heatsink. Make sure it's tightly latched in place. Try setting the computer on its side so the heatsink sets down on the proc.
4. Maintenance on h.d. Defrag, etc.
5. If all else fails, start unplugging/swapping things. Swap the video cards, unplug and replugin the power cord, unplug any peripheral PCI cards, etc.

 

[stevty2889]

Did all the used parts work fine before? Did you mount the motherboard properly on the standoffs? Any loose screws that might be in the case?