Only thing to do, probably, is to do a hard reset following these steps
1 - Switch off the device
2 - Press and hold the Volume up button, the Power button and the Home button at the same time.
3 - When you feel the device vibrate, release ONLY the Power button
4 - A screen menu will now appear. When you see this, release the remaining buttons
5 - Use the Volume down button until you are highlighting 'Delete all user data'. Press the Power button to select.
6 - Press the Power button again to select the Yes - delete all user data option
7 - Press the Power button to highlight, then select the 'reboot' option