I recently dropped my Iphone 4s 32gig phone on the ground and the screen did not crack or anything. When i tried to slide to unlock it, nothing happened. It woudn't read my finger at all and the phone seemed fully functional (meaning i could click the unlock and lock buttons and home buttons and it all worked fine, it just seemed like the sensor was not reading my finger). So i figured it was a problem with the LCD screen so i purchased a new one and installed it correctly, and nothing happened. Something else is wrong with my iphone and i have no clue what to do. Can anyone help me?