Ok i'm using a A665 I know as fact these laptops have a power button issue the button clicks up and down by way of a plastic bubble making contact to turn your laptop on and off it could be that the button is stuck down and not popped back up then again it maybe permanently stuck down. This can be diagnosed by opening laptop and removing the cable from this button that attaches to the motherboard there is a youtube video on this but I'm unable to locate it at present.You leave it unattached and turn your laptop on and off plugged in by mains.
Or you could wait out a while if left alone the button may release back up.