I recently dropped my phone n cracked the screen but the touch screen part works fine. however, it wont stay on unless its on the charger. occasionally, i can take it off and it will stay on for bout five minutes but eventually turns its self off. and when i try to turn it on only the apple symbol shows up for a few seconds and then disappears. and when i plug it up to a charger the same apple symbol appears n then eventaully turns its self on and stays on as long as its attached to the charger. Any suggestions??? thx