Details of the new Xbox have started to vent out and the latest is the new Xbox slims way of tackling the overheating problem, it shuts off. If the vents or fan get blocked some how the Xbox will warn the player and shut off, turning the power button red. The Xbox will not be able to turn back on again till the red power button switches itself off.
These images were taken from the Neo Gaff forums but don’t worry, it looks like this guy purposely tried to over heat the console to see what would happen. Some people have money to burn.