I dropped my phone on the stairs yesterday. The battery and the back casing fall out too. So,I quickly take them and put them back to the phone. But luckily the phone doesn't have any scratches. Then when I on my phone, the screen is black BUT the light of the keypad is on. I tried using my dad's handphone to call mine. It vibrates and still in a good function of the sound. Everything is in a good function but just the SCREEN WENT BLACK. What should I do? I even tried taking out my battery and put it back and on it back but still it doesn't make any difference. IS STILL BLACK! Please HELP! 