Summarize this article in one sentence.
On your Xbox 360's Power button, there will most likely be one to four red flashing lights displaying around the perimeter of the button; these lights pertain to different problems. If you don't see an error code when you turn on the Xbox 360, skip ahead to the "Replace the power brick" step. Depending on the number of flashing quadrants, the problem could be one of four main things:   One red quadrant — Displays when a hardware component (e.g., the fan or a connected USB stick) stops working.  Two red quadrants — Signifies that your console has overheated. This will normally go away on its own, but you can take steps to ensure that it doesn't happen again.  Three red quadrants — Indicates that a serious error regarding one or more hardware components has occurred. This is the infamous "Red Ring of Death" error.  Full red circle — Indicates that an A/V connection has been lost. You won't see this for Xbox 360s which use HDMI cables. If you see one red quadrant light up on your Xbox 360's Power button, you'll also see an error code appear on the connected television. Since there are numerous codes you might see, the easiest way to address your specific error is by typing the error code followed by xbox 360 error into a search engine, selecting a reputable search result, and following the instructions. Unfortunately, you'll have to take your Xbox 360 in for repairs if you can't address the error by looking it up. While your console's two flashing red lights will disappear on their own after the console comes down in temperature, there are a few things you can do to prevent your console from overheating in the future:  Make sure the console has plenty of space in all directions. Lay your console horizontally, not vertically. Clean any dust out of the console's vents (you can use a damp cloth or a vacuum for this). Keep the console in a cool, dry place; avoid having it in the sun or near a heater. . The Red Ring of Death is somewhat non-specific, but you may be able to fix it by applying a new layer of thermal paste to your Xbox 360's heat sinks. As with most internal issues, the Red Ring of Death is a problem best left to professionals. The easiest way to fix this error is by using an HDMI cable to connect your Xbox 360 to your TV; if that isn't an option, check your current A/V cables to see how they're plugged in. If they're loose, tighten them and then restart your console.  If your A/V cables are fine, you'll need to replace them. If the error continues displaying even when using new A/V cables, your console's A/V input may be broken. You can either send your console in for repairs or switch over to a different display that allows you to use an HDMI cable. Microsoft's official policy for a CD drive that's stuck open is to wiggle the tray from side to side, wiggle it up and down, and then gently push it shut. If pressing the "Eject" button doesn't prompt the tray to pop out, you'll need to take the Xbox 360 in for service.  If the CD drive is stuck shut, you can try opening it by pushing a bent paper clip into the "Eject" hole on the front or back of the console. If this doesn't work, your Xbox 360 needs service. If the CD drive works but won't read two or more of your game discs, try removing any attached USB items. If it still won't read your discs, you'll need to take your Xbox 360 in for service. For problems not related to an error code (e.g., unexpected shut-downs), you may need to replace your Xbox 360's power source. This is because Xbox 360 power bricks have roughly 5 years of life before they begin to malfunction.  Malfunctioning power bricks can also cause your Xbox 360 to freeze or otherwise under-perform. If your Xbox 360 won't turn on even after replacing the power brick, check the USB slots to see if any of their connectors are bent. Bent connectors can cause the Xbox 360 to fail to turn on; if they are bent, prying them loose with a screwdriver may fix the problem. If you use an HDMI cable and your Xbox 360 isn't displaying video properly, you can try using a different HDMI cable to address the problem. Keep in mind that the problem may also lie with your TV, in which case you'll either need to use a different HDMI port on your TV or use a different TV entirely. If none of the above instructions have fixed the problem you're having with your Xbox 360, you'll need to send it in for repairs.

Summary:
Look for an error code on the Xbox 360's Power button. Determine the error's meaning. Fix a non-working hardware component error. Address a console that constantly overheats. Attempt to fix the Red Ring of Death error Fix the full red circle error. Fix a broken CD drive. Replace the power brick. Try using a different HDMI cable if your video is acting up. Take your Xbox 360 into a repair service.