Your personal settings were probably reset after you had switched off your TV because it is still in the LOCATION SHOP mode. In this mode, all settings are fixed and will automatically apply each time the set is turned on.
To store your personal settings, make sure your set is in LOCATION HOME mode:

1. Press the MENU/BROWSE key on the remote control.
2. Select TV menu and press the button
3. Select Installation and press the button
4. Select Preferences and press the button
5. Select Location and press the button
6. Select Home and press the OK button
7. Press the MENU/BROWSE key to browse through the menu