Lights turn on so a problem with the PSU is highly unlikely. Sorry, I think it's your MB. Scorching is a bad sign. I'm guessing the system was up and running for a while, this is not a new build? Were you doing anything naughty..??? A little OC maybe, little bit of overvolt...?If the damage is on the board I think you're done for, but you can try a different PSU to put your mind at ease.