Although my problem is cleared up now, I thought I'd post this in case anyone else experiences this problem. The fix turned out to be fairly easy, but the overall experience was annoying.
I was watching TV this afternoon and switched to a channel but it was blank and no sound. Tried other channels, and some more but not all of them were blank and no sound or some of them stated I was not authorized to get that channel (which I was supposed to be). These are channels I have in my package and regularly watch.
Nothing had changed, been unplugged, reset since I was watching TV at the time this happened, nor has anything odd happened in the very recent.
I called Tivo and they had me do a variety of things, including rebooting, reloading channel line up, and she checked several of the cable card screens only to say they looked good. She suggested I contact Time Warner Austin.
One other odd thing I noticed before I called TWC. My low channels (local) were all HD now, but I still had my high number (local) channels that I could also tune to. I checked the info and whereas the low local channels used to always be 480i they were now 1080i. Very strange. They definitly were in HD too, it was easy to see the difference.
I called the TWC cable card hotline and explained all of this to the guy. First thing he had me do was unplug the tuning adapter for 15 seconds and replug it back in. After a few minutes when the light went solid again (as it was before I did this), I got all of my channels back and all of my low local channels were back to 480i.
So I don't know what happened, but apparently my Tuning Adapter 'belched' or something without being obvious about it.
If there is another thread that already explains this then my search tactics need improvement because I didn't find it, so I thought I'd post it in case this helps someone else out.