We had a very brief power outage. After power came back on, we realized that the den DVR had lost all saved programs and was deleted from the other 2 DVRs. We can get channels but we cannot tape shows.
The disk may be fried. Obvious first thing, which you may have already tried, is pull the plug and wait a few minutes before powering up again. Until the DVR does shows your recorded programs, their is no point in trying to get the other STB's to see it.
If the DVR does work you can try the options in the menu to fix Muliroom DVR.