iPhone wont turn on Black Screen
So I recently dropped my iphone 4 the back screen cracked but the front screen is in perfect condition .However when I tried to turn my phone on it wouldnt turn on and the screen would just stay black .When I plug it in to the computer it made the charging noise and was vibrating , so I know it still works but still nothing shows on the screen .My friend thinks the LCD screen is disconnected.
Any Solutions?