Resetting a mobile phone back to factory settings completely erases all of the data on the device. Pictures, emails and music will be erased during the reset. Applications and ringtones added to the device also are erased. If you are returning the phone to the store or giving the device away, erase the data on the phone. Any information left on the phone can be accessed by anyone in possession of the device. Although the procedure varies by phone, most mobile phones can be reset back to factory settings by accessing the security settings on the phone.
Press the "Menu" key and select "Settings."
Scroll through the options using the "Up" and "Down" arrow keys. Select "Security."
Select "Reset Phone" to completely erase all of the data on the phone and reset it back to factory settings.
Wait for the phone to power back on. Most phones need to perform a restart to complete the reset.
If you are unable to reset the phone to the factory default by accessing the security settings, refer to the owner's manual for the phone. You also can contact the mobile service provider for further assistance.