Xbox 360 screen cut off?

when i play my xbox 360 i notice that the tv's screen size changes from ';full'; to ';natural'; which cuts off part of the screen on all sides when im playing games. its like the picture is too big for the tv screen. when i try to change to screen size back to full, it says ';not available'; and wont let me. how do i adjust the screen size to ';full'; so that the screen doesn't get cut off?

(note: xbox is set on 720p widescreen and the tv is widescreen)

thanksXbox 360 screen cut off?
make sure that your playing on the right station. for me i have to be on component 2Xbox 360 screen cut off?
Make sure that the little switch on the side of the composite/componant video cable is switched to HDTV and not SDTV I think it is... It is on the end of the cable that plugs into the 360. This might be the problem...hope that helps.

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