It red ringed today, my 360. I unplugged it and tried it three times over. Called the support number, and getting it fixed.

I know whats wrong with my 360 - it's the fan. it's become louder over recent months, and I notice a huge difference between the sound of it between a normal xbox and mine now.it also explains why mine is worked again. I just don't think it's cooling properly and the Fan isn't working right. Just like your PC - if it doesn't cool right, it's gonna shutoff.