Resetting the Xperia ARC S phoneYou can reset your phone to its original settings, with or without deleting all of your personal data. It is possible to reset the phone to the state it was in before you first turned it on. But before you perform a reset, make sure to back up any important data saved on your phone.
To reset the phone
1. From your Home screen, tap .
2. Find and tap Settings > Privacy.
3. Tap Factory data reset.
4. To erase not only internal storage but also other user data such as pictures and music, mark the Erase SD card checkbox.
5. Tap Reset phone.
6. To confirm, tap Erase everything.
A hard reset will reset your phone to factory default settings. All files and configurations that you have entered in the phone will be lost. After the hard reset the phone will reinstall Windows Mobile and the software included.
Note: Backup the files that you want to keep, before you perform a hard reset. You can backup files via a computer or a memory card.