This is happening to me too, one minute I am happily playing Skyrim.. (then it froze, I left it on all night :( but this has happened before.) I tried doing what Microsoft said on their website, but then this update came up and I cant update it because I don't have enough storage because I had to take my hard drive out again, so when I pressed no for the update it froze, every single time. I am dying to find out what is causing it (I might check the hard drive again...) or try to hook up my Xbox 360 to my computer.