Direct tv Dvr keeps restarting on it's own!?

It has been happening for months now. My Dvr Keeps restarting. It happens all the time. It sometimes happens several times in a row. Monday it restaring 4 times in one hour. It is so frustrating, I was having an SNL/Micheal Phelps party a few weeks ago, it went out 20 minutes into the program and didn't come back on until the morning! I am very upset, it is my dad's tivo/tv, but he has his own hd stuff upstairs and basically said he didn't care if it worked or not. I'm upset if anyone has any suggestions that don't involve me calling a repair man they would be greatly apprechiated! Thanks