Please note that all data will be deleted from the Sony Ericsson Xperia Arc as a result of this procedure.
This process may or may not delete data stored on the microSD card. We recommend backing up all of your personal data before proceeding.
First, try this:
From the main home screen, tap menu
Tap Settings, then Privacy
Tap Factory data reset
Tap Reset phone
Enter your password if required, then tap Erase everything to confirm
If that doesn’t work, or if your phone is frozen:
Turn the power off. If your Sony Ericsson Xperia Arc is frozen, pull the battery out and reinsert it
Hold the Left and right buttons located beneath the display
Press and release the Power button
Follow the on-screen instructions to hard reset your phone
All data including third-party applications will be deleted from the Sony Ericsson Xperia Arc.
Once the wipe is complete, the phone will reboot to its factory fresh state.