I don't think it's hte processor becuase I've turned on a computer without a processor in it before. and it still starts.. just no display or anything, but the fans and the drives all came on (yes atx, not an at). The stupid stuff I did when I was younger messing wtih pc's haha... but yeah I don't think it's cpu. Maybe bad button or wires on the button, or else perhaps it got a surge and the board's fried. Newer power supplies don't turn off 100% like the old kind did, therfore electricity is still flowing through it all the time.. Surge protector or not it could still happen trust me. My mom's got hit by lightning once and the surge protector was all over the floor when I found it after that. Her computer was fine becuase it was the old kind with a switched button not a soft type button. Surge protectors can help surges but still they don't stand a chance against lightning. So that's a possibility that it could have been hit by lightning.. Lightning can cause strange things, trust me I know that, I lose something every year to lightning strikes, and I myself have almost been hit twice...