Samsung i710 soft reset
Use this method to hard reset your Samsung i710 phone: Enter *2767*3855#. Warning! All your data including contacts, messages etc. will be lost! Copy all your necessary data/Contacts/Messages etc. to SIM or make backup to your PC before full reset! Take out SIM card before full reset.
Or Samsung i710 hard reset with buttons / keys
Turn off your i710 phone. Press WIN + OK key + Press RESET together for at least 1-2 sec