first remove sim card and memory card than try this all method.
1. turn on your device.
2. tap menu screen.
3. than tap Settings, then Privacy
4. Tap Factory data reset
5. Now Tap Reset Phone
6. when ask you password enter the password than tap Erase everything
if you can't solve your device problem or device is not turn on try
1. Turn Off Your Device remove battery and reinsert.
2. Press Hold the Left and right buttons located beneath the display
3. Press and release power button.