It occurs to me that you might need to go through guided setup again to straighten out that double channel thing, and I can't think of what accidental key presses could have caused it, so you can let him out of the doghouse
Before you do anything else, drill down through the menus until you get to "Restart the TiVo DVR" and do that, and after you press the thumbs down 3 times and are about to press "enter", be ready to unplug the power cord from the wall socket/UPS as soon as you do press enter and the screen goes blank.
Let it sit for a few minutes, then plug it back in.
If you've still got the problem, then you can go through GS again. You'll need for the cable box to be feeding a video signal into the TiVo when you do.