It has occurred to me that maybe I should mention this...
Electronics and specifically, PCs do not like static electricity. W/out explaining the science or physics of it here is my point... Often I have gone to clients' homes or offices and discover PCs sitting on carpets. Remember, if you rub a balloon on a carpet it will then stick to a wall? That's static electricity @ work. DO NOT sit PCs directly on carpets. IF, the machine is going to be placed on a carpeted floor put something under it to isolate it from the carpet; a wooden board, newspaper, cardboard, you get the idea.
And another thing, while I'm @ it... do not remove or replace PC case covers, side panels and such whilst a PC is running. Always do this ONLY after & while the machine is unpowered or shut off.