DirecTV DVR Box on the Fritz? It's Not Just You
If your DirecTV DVR box took itself offline late yesterday afternoon or early evening (or earlier depending on your time zone), don't worry, there probably isn't anything wrong. I experienced this myself, and come to find out, it was a SNAFU on DirecTV's part, and not a sign that my receiver was about to give up the ghost.
According to Fudzilla, only DirecTV DVR units appear to have been affected by the seemingly random lockup. Apparently there was an issue with a program guide update that confuzzled DVR boxes to the point where they froze and/or shut down. Making matters worse, DirecTV was attempting to push out a software update at the same time, which just led to more problems.
If your box is still locked up, you should be able to bring it back to life by pressing the red button behind the access card door on the front and letting it run through its cycle. Once it finishes, press the red button a second time within 30 minutes. What this does is delete the corrupted program guide information, forcing it to reload.