Reset to original factory settings by entering: *2767*3855#
The phone will reboot.
Then insert a SIM Card that is from another network that your phone is not locked to.
A "Wrong SIM" message will come up on the screen
When message appears enter: *#9998*3323#
At this time a white screen will appear which says "exit"
Tap the right soft key, (occasionally it will not go to the next screen, if so press the down key)
From the menu that appears scroll down to the malloc Fail option, this will reboot, and normal service screen will appear.
Then type *0141# and press the green call key, "Personalized" will appear on the screen, and the name of the current SIM Card provider will appear on the screen.
Turn phone off, and then turn on.
Go to menu by tapping left soft key, then settings in bottom right hand corner, then choose option number 7, security, then choose option number 6, SIM Lock, select option 1 disable.
Then enter 00000000 (eight zeros), the message will come up SIM Lock disabled with a check mark, your phone is now unlocked to use with other carriers.