rf 52?

Hi. Our DVD/VCR combo has all of a sudden shown RF 52 on the front. I'm not sure how it happened but when I was putting in the scart lead it suddenly came up with that on the visor part and Auto Installation and I'm not sure what I pressed and how to get our channels bakc on it as we also have no remote. Any ideas how:

a) I could've got this without remote
b) how to get our channels back using the menu?

Would appreciate any answers.

Thank you.