Quote Originally Posted by NeoGen
I know a guy at a computer store that says he receives dozens of computers, supposedly with malfuctioning motherboards that in the end are totally fine.

I've witnessed him twice taking the motherboard off the case of machines that were not working at all, putting it on top of a plain card board, plugging again the PSU, CPU, RAM, and gfx card, and it worked again!

He says he hasn't got a scientifal explanation, but maybe it was a kind of short circuit and the board must be conducting electricity to the metal case somehow, maybe through one of the screws.

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i've seen this many times. the screws that screw into the stand offs are too tight sometimes and short the board out.