Note: A hard reset process will wipe or delete the data stored on the device, so make sure to back of all important files you've installed or stored on the phones memory. However, this may not harm the files stored on the microSD memory card.
Factory Reset by Settings:
This can be done from Main Home Screen
then select SETTINGS, then PRIVACY
select FACTORY DATA RESET and then RESET PHONE
then choose ERASE EVERYTHING
This will wipe the present settings and then restore back the device to its factory settings.
If your Xperia X10 Mini or mini Pro experienced Hang or Freezing problem.
Sometimes you may just stuck on the start up logo, this may help if you can't access or get through to the home screen. If this happens you may reboot the phone by way of pressing button combination and do a hard reset.
- Turn the power off or remove the battery out and reinsert it back again.
- Hold the Left and right buttons found beneath the LCD display
- Briefly Press and release the Power button
- Follow the steps on-screen to hard reset your phone
If somehow if the hard reset will not fix hang or frozen problem, the only and final option is to restore or flash the phone's original stock ROM or firmware.