I was at work charging my phone when it suddenly fell off the chair. It has the rubber case on,the one that absorbs impact. When I picked it up, the screen was blank. I kept pressing the power button but nothing. I know the phone is on because the physical keyboard backlight still turns on when I slide it out and press the power button. Would anyone know what's wrong? P.S: I already took out the battery and it didn't change anything.