1. Insert an original SIM card and turn the phone on
2. Access the hidden menu by typing
3. Select 'Menu' and then 'Settings'
4. Next, select 'Security'
5. Select 'Network Provider' and 'Deactivate'
6. Finally enter the Unlocking Code provided. (Please note: Some phones require a slightly different access code - please see the list below if the above access code doesn't work for your phone.)