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 LG Optimus One is frozen, pull the battery out and reinsert it
Hold the Home and Volume Down button
Press and hold the Power button until the device turns on
Follow the on-screen instructions to reset your device
All data including third-party applications will be deleted from the LG Optimus One. Once the wipe is complete, the phone will reboot to its factory fresh state.
Il duci la o firma care repara telefoane sau la firma LG cred ca trebuie umblat in telefon.