So you plug it in press the power Button, and don't Get any noises ..
No Beeps, no Fans, No Flashing lights?
Well if thats the Case the First thing to Check would have to be the Power Cable, then The Connection Of the Power Supply to everything else, and then the power Supply its self.
... when i have a computer that wont work, i Remove Every thing Except the CPU, Mother Board, case and Power ...
Then it should Beep