We have a THR22-100. This morning our power went out and didn't come back on before we all left for work/school. When I got home this evening, my son said that the Tivo wasn't working. I sat down to find that it was asking me to go through the Guided Setup. Seemed a little strange since its been powered off intentionally and unintentionally before and never required the Guided Setup before, but I started to go through it again regardless. When I got to the satellite setup, I honestly wasn't sure which option to choose. I called DirecTV technical support and after a trying a few of the satellite options and not getting much help, I finally went with a configuration that the box told me wasn't quite right. Fortunately, it appears that my channels are coming in correctly. Unfortunately, and much to my dismay, not only had all of my settings been cleared, but all of my shows and scheduling as well. The tech support guy was totally unhelpful and just said "this is just one of those things, it probably won't happen again"
Anyway, not sure what can be done, but FYI, if you lose power, you might also lose all of your setup and shows.