My laptop has done this several times in the last year. For what appears to be no reason at all, and regardless of how it was shut down, it just won't do anything. It won't turn on, so obviously, it doens't do anything else, right?

NOW, I AM NOT ADVISING OR ADVOCATING THIS....BUT, this is what I have done. I dissconnect all cords, plugs, etc. I pop out my ethernet card, I pick it up and put it back down in another location, and hook everything back up. I have, on occasion, 'shaken' it, too. Not vigorously, and certainly never more than it gets jostled around in carrying it..but, it works after that.