I posted a question the other day regarding this issue with my machine, and before I replace the hard drive I was wondering if it is possible the power button is stuck? It doesn't look like it is, but it sounds like it could be. I'll link the video I made again. Just wondering if anyone's come across something similar...
http://s256.photobucket.com/albums/hh168/roxstarrgirl/?action=view¤t=VIDEO0098.mp4
http://s256.photobucket.com/albums/hh168/roxstarrgirl/?action=view¤t=VIDEO0098.mp4