Why won't my DVR come back on?

Every few weeks my Contour 6 DVR will go off (brief power outage during winds or just random outage). When it tries to start back up, it can't get past the Welcome screen. I unplug it, wait for 10 minutes or so, then plug it back in. Same thing happens. This goes on for hours. When I call for help, I'm always patient while the tech follows the usual script, to no avail. After a valiant effort to help me, the tech always schedules a service call. At that point I unplug the DVR once more and go to bed. The next morning, I plug it back into the power outlet and it magically restarts with no problem—after which I cancel the service call.

What is going on? How can this be fixed? It ** that, whenever this happens, I have to wait until the next day to have any TV services.