A master reset will result in the loss of all data stored on the device including 3rd party applications.
This type of reset should only be used as a last resort after all other troubleshooting steps have been exhausted. It is highly recommended that you complete a backup of the device information before proceeding with the steps in this tutorial.
From the home screen, tap the Menu key.
Tap System settings.
Scroll to and tap Backup & reset.
Tap Factory data reset.
Read the warning and tap Reset phone.
Note: To erase the contents of the memory card during the reset, tap to select Erase internal SD card. Once content has been removed from the memory card, it cannot be recovered.
Read the warning and tap Erase everything.
The handset will completely reset and restart.