360 video issue
I have one of the original 360 premiums and have been more than happy with it. Everything has been working fine until today. After leaving my 360 untouched for a week, I decided to go get some Fable 2 time in while my girlfriend is out doing errands. When I boot up the system, it tells me there's an update waiting to be installed. I let it do its thing, and once the install is finished, I boot up Fable 2. The game lasts for all of a minute, then will do any of the following: screen suddenly becomes wavy snow, screen suddenly goes black, screen suddenly goes to a very dark blocky texture reminiscent of an aging NES struggling to output video, and so on. I've tried a few different things, both in game and just in the dashboard, and the loss of video always happens. While video is out, the 360 doesn't show any unusual, ominous red rings.
So what are my options? My first thought is that the update has managed to brick my 360, but I have no idea how I can roll back updates, especially since I don't get a lot of screen time before the machine asplodes. Is there anything I can try, or am I destined to have a rousing discussion with my friendly neighborhood MS CSR?