had this reply from samsung-may help
What you are describing indicates the television may be in a mode, which
is called 'Shop Mode' this is basically a mode which is intended for
retail use, the television will default back to factory settings within
a certain time period. The television should be in 'Home Mode', to
switch the television back to normal mode you need to follow the
following steps.
Menu > Set-Up > Plug & Play
Please note that if you are using Freeview or Sky/Virgin you must press
the TV/DTV button first. You will need to go through the plug and play
procedure completely including the full channel re-scan to save setting
change. Shop Mode is designed only for retailers, as Samsung doesn't
know what modelwill be a display model they all have this built-in
feature, full details are in the user manual.
good luck
tinkyw1nk, February 2009