If your phone still does not turn on then it’s time to attempt a factory reset. Make sure to only perform this procedure if you have previously made a backup of your phone data.
Turn off the device.
Press and hold the following three buttons at the same time: Volume Up key, Home key, Power key.
When the phone vibrates, release the Power key but continue to press and hold the Volume Up key and the Home key.
When the Android System Recovery screen appears, release the Volume Up and Home keys.
Press the Volume down key several times key to highlight ‘wipe data / factory reset.’
Press Power button to select.
Press the Volume down key until ‘delete all user data’ is highlighted.
Press Power button to select and start the master reset.
When the master reset is complete, ‘Reboot system now’ is highlighted.
Press the Power key to restart the device.
If your phone still does not turn on then this may already be a hardware related problem. Bring your phone to an authorized service center and have it checked.