Here's, how to hard reset the Sony Ericsson Xperia X8 with simple step by step instructions.

Please note this process will delete all data from the Sony Ericsson Xperia X8 , but may or may not delete the data stored on the microSD memory card. Do have a back up or a copy of all your personal data before you may proceed.

Restore through the Main Home Screen Settings

1. From the Main Home Screen, select Menu
2. Select Settings, then select Privacy
3. Select Factory Data Reset
4.Then Reset Phone
5. Enter the Password if prompted or required, then select Erase Everything.

If the phone is frozen: You can Hard Reset it trough key combination.

1. Turn the power off first. If the Sony Ericsson Xperia X8 is frozen, take the battery out from the device and then reinsert it back again after a few seconds.
2. Hold the Left and Right Keys located beneath the LCD Display
3. Press and release the Power Key
4. Just then follow the on-screen instructions that appears to hard reset the Sony EricssonXperia X8

Once the wipe process is complete, the phone will then reboot to its factory fresh default state settings.
All data including third-party applications already deleted from the Sony Ericsson Xperia X8.You may need to reinstall it back again.