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How do I Lock my Samsung Focus®?
Your phone supports a screen lock feature, and a lock code feature.
When the screen lock is activated, you will need to press the Power button, and then flick up on the screen to unlock your phone.
The lock code feature requires you to enter a lock code after you flick the screen up to unlock the phone. To activate the lock code feature, flick left to the Apps list from the Start screen, and tap Settings > lock + wallpaper. Tap the slider next to Password to turn the lock code feature On. Enter your password in the New password box, and then enter the same password in the Confirm password box, and tap done.
You can lock your phone at any time by pressing the Power button. Your phone will automatically lock itself according to the Screen times out after setting that is also available in the lock + wallpaper settings screen.