Reoccurring Xbox 360 problem….?

I’ve had my Xbox since Christmas 2007. I’ve never had to get it repaired. Recently I’ve come across a problem. One day, when I’m playing with absolutely no warning, the console shuts off with absolutely no warning, and there are two flashing red lights in the left quadrant (counting four lights, the first and third are blinking red). I walk up to it and prss the power button, nothing happens. The only way to shut it off is to unplug the power supply. I look it up and it says its warning me that the console is overheating. It says to let the Xbox cool and try again. So I let it cool for a little while and try again. Doesn’t work. I’m even extending the time to more than a week and it still isn’t working. Just today I go to the dashboard and download Map Pack 2 (extremely slow system, takes like 1 hour, but that happened even before the red light thing) and once I start playing it, the game lasts for 15 minutes at the most and shuts off. Yes, all of the plugs are properly connected. Thanks for your help.