Sony KV-9PT20 TV Can't Remember Channels! WHY!

It can move up channels and I can enter channels.

When I autoscan channels it works. When I push + and -, I see channels
supposedly being added.

BUT, when I push the Channel Up button to look at the channels,
NOTHING has changed.

This happened over 1 year ago. I don't know why but now it refuses to
remember, add or delete channels.

WHY?

Is it the TV? Memory chip? Battery in TV?

Is the memory in my Remote? I did drop the remote but the buttons
function properly.