Summarize this article in one sentence.
The ring of lights around your Power button can indicate what kind of problem you are experiencing. This can help determine how to go about fixing it:  Green lights - The system is operating normally. One red light - This indicates a general hardware failure, and is usually accompanied by a code on your TV screen (e.g. "E74"). See the next sections for some tips on getting this fixed. Two red lights - This indicates that the console is currently overheating. Turn the Xbox 360 off for a couple of hours and make sure that it is ventilated on all sides. Three red lights - This is the Red Ring of Death, and indicates a major hardware failure. This usually occurs because the motherboard has overheated and become warped, causing the chips to lose contact. You'll need to either open up your system and repair it yourself or send it in for professional repair. Four red lights - This indicates a faulty or unsupported A/V cable. Your Xbox 360's power supply also has a light on the back. This light can help you determine if your power supply is failing:  No light - The power supply is not receiving power from the wall. Green light - The power supply is working correctly and the Xbox is on. Orange light - The power supply is working correctly and the Xbox is off. Red light - The power supply is failing. The most common cause is an overheating power supply. Unplug it on both ends and let it sit for at least an hour.

Summary:
Check the lights on the front of the Xbox 360. Check the light on your power supply.