Do you mean a Matsui? (Dixons, Currys own brand.) and is it a Widescreen TV? If it is then either you are watching channels that are being broadcast in 4:3 mode. Or a you have it connected to a set top box that is set in 4:3 mode. Or you have the TV set to 4:3 mode. Go to the menu and reset it to widescreen. It's all in the manual. If you don't have a manual try Dixons/Currys.
Terry
October 2006