my phones front three buttons (back) (window) and (search) won't work. I haven't hit it on any thing or dropped it in water. I just restored my phone and the battery was too low. I plugged in the charger and the phone restarted by these buttons won't work. I have restarted my phone several times but nothing is happning. I can feel my phone vibrating on touching these buttons as it should be it isn't doing what it should do. So plz tell me some thing useful.