It seems like a common problem where some people's macbooks suddenly stop working without a charger. My mid-2011 15 inch model doesn't seem to turn on from sleep mode without a charger. The difference is that it continues working without the charger attached once it is able to turn itself on with the supporter of the charger, so I am assuming that the battery is not broken theoretically. When it does boot up from sleep mode with the aid of a charger, the screen turns on as it was when I closed the computer screen with a blurred layer on it. Then a meter appears at the bottom and it takes around 20 seconds to fully boot up. Is anywhere aware of this problem that I am having? I'd appreciate some help. Thanks EDIT: This is the screen that I was talking about when I actually do connect my charger after it fails to bootup from sleep mode.