Perform a soft, factory, and alternate master reset of the device.
INSTRUCTIONS & INFO
To reset your device, from the home screen, swipe down from the Notification bar. Note: Performing a factory reset will permanently erase all data and personal information. This action sets the device to its original factory settings.
Tap the Settings icon.
Scroll to, then tap Backup & reset.
Tap Factory data reset.
If desired, tap Erase SD card.
Tap Reset phone.
Enter the Prompted number.
Tap Erase everything.
If unable to reset the device using the above steps, try the alternate master reset method by first powering the device Off.
With the phone powered off, press and hold the Volume up and Power keys together for 2 seconds, then release them.
Press the Volume down key until "Recovery" is highlighted and then press the Power key. The device will restart.
Press the Volume down key until "wipe data/factory reset" is highlighted, and then press the Power key.
Press the Volume down key until "Yes - delete all user data" is highlighted, and then press the Power key.
Press the Power key to select "Reboot system now".