This info was acquired from the Samsung Solstice Manual PDF file I tested this to make sure it worked on my Solstice. By the way, that link is the complete user manual for the Samsung Solstice, I found it to be very helpful. 1) Go to: Menu > Settings > Phone > Security. 2) Scroll down and touch the "Change Phone Password" field. 3) If there is a password already set, enter the current phone password and touch "OK". Otherwise, skip this step. 4) Enter your new phone password and touch "OK". 5) Reenter the same password and touch "OK" to confirm. 6) Touch "On" from the above "Lock Phone" field. And you should be good to go! Hope that helps. :)