Is your PSU set for the correct voltage where you're at i.e. 110 or 220.....sounds like a problem with building electrical or the PSU is really going crazy
Well, flip the voltage switch on your PSU (if it has one) or try plugging the computer into a different circuit.
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+1 set it to the proper voltage, try it maybe in the kitchen or a far part of the house, either 'should' put you on a different electrical circuit, where you're at could be miswired, possibly ground and neutral reversed or even no neutral