You can reset your Sony Xperia acro S to its original factory settings which is the state it was in before you turned it on for the first time (of course all your personal data and customized settings will be erased then). You can also reset the phone to the original settings without erasing your personal data. It is strongly recommended to back any important data saved on your phone. To avoid permanent phone damage, do not restart the phone while a reset procedures is underway.
Resetting Sony Xperia acro S without erasing personal data
1. From your Home screen, tap
2. Find and tap Settings > Backup & Reset.
3. Tap Settings Reset > Reset Phone.
4. To confirm, tap Reset Settings.