1. Grab a towel or two.
2. Wrap your 360 up in the towels, so that all of the air vents are completely covered.
3. Turn on the system and let it run for about 20 minutes. The heat building up from it being covered up will overheat the system, giving it the 3 red rings of death.
4. The side effect of this is that it resets your system, and you can start it right back up after letting it cool down for 20 minutes or so, after you unwrap it and all that.