Guide Plus problems?

My RCA TV worked fine until I had a power failure. Since then, the stupid Guide Plus 'demo' comes on every time I turn the TV on. It takes about 5 minutes to get this stupid thing to go off, and then there is a little rectangular box that says "Guide Plus" and it changes positions on the bottom of the screen every couple of minutes.

I tried what was said on this site, going into settings and setting the zip code to 00000, but I can't even get INTO that part to even do it.

The demo says something about pulling a "pin" on the back of TV, but there IS no pin. The TV works FINE otherwise, but it gets tiresome having to wait all that time to even SEE the screen, then having to keep pressing the 'up' or 'down' volume keys to remove that stupd BOX!

PLEASE HELP. I emailed RCA and got NO answer.