Well that says it all, turned on the TV as normal, it's stuck on one station and I can't persuade it to move, etc and can only turn it off at the power, and when turned back on again, it's just the same !! I've obviously hit something i shouldn't but does anyone know what ?? I don't !!
Just a thought:
Is your TV set connected to any other device, such as a satellite receiver?
If so, it's possible that your TV's input source is set to take a signal from that device. So, in order to change channels you'd need to change it on the external device, rather than on your TV. (If that's the case, press the Source button - indicated by a rectangle with rounded corners and an arrow pointing into it - to change the source back to 'TV', 'DTV' or however your system labels it)