Do a factory reset to return your phone to its original state before the first time you turned it on.
If you’re passing your phone on to someone else or your phone has a persistent problem that cannot be solved, you can perform a factory reset (also called a hard reset). Factory reset is not a step to be taken lightly. It’ll permanently delete all your data and customized settings, and will remove any applications you’ve downloaded and installed. Be sure to back up any data and files you want to keep before you do a factory reset.
Performing a factory reset via settings
The most convenient way to do a factory reset is via the phone settings.
1. From the Home screen, press MENU, and then tap Settings.
2. Tap SD & phone storage > Factory data reset.
3. Tap Reset phone, and then tap Erase everything.
Performing a factory reset using the phone buttons
If you can’t turn on your phone or access the phone settings, you can still perform a factory reset by using the buttons on the phone.
1. With the phone turned off, press and hold the VOLUME DOWN button, and then briefly press the POWER button.
2. Wait for the screen with the three Android images to appear, and then release the VOLUME DOWN button.
3. Press VOLUME DOWN to select FACTORY RESET, and then press the POWER button.