well same thing happen to me. my computer still can't get out of sleep mode. but to solve your turning the computer ON problem. what I do is turn it on, then wait, u will hear the computer turning itself on and off, but nothing is showing on the screen. so make it turn on and off, 3 time.( such as hearing the computer turned off, so that one,THEN IT TURNS ITSELF ON AGAIN, next time it turns off, that count as 2, and so on). on the third shut off then u press and hold the off button, to force it to shut down, then wait. about 5-10min., or less then 5. after then u turn the computer on.it should be on by now. if not try it again. if it happens again try one more time, if it happens again. then there something really wrong with your computer.
HOPE THIS HELPS.