Hi my acer aspire 7551 series laptop will not turn on after shut down. When power button is pressed there is no response at all (no lights, sound, etc). I've tried taking out the battery and holding the power button down and then reconnected the charger, still no response. If I let it sit for a few days it will start up normally, as if nothinh was wrong. This has happened quite a few times now and its extremely frustrating. Any ideas that may help?