How to Troubleshoot Two Red Lights on Xbox 360
Two flashing red lights on the left side of your Xbox 360 Power button indicate that either your console or your power supply is overheating. You can resolve this problem by taking the appropriate actions to cool down your Xbox 360 console and making sure the vents on the console and on the power supply are not blocked. If you encounter this problem on a regular basis, you risk melting parts inside of your console or ruining your power supply. When the parts inside of your Xbox 360 begin melting as a result of overheating, you'll encounter the dreaded three flashing red lights, also known as the Red Rings of Death.
Let Your Xbox 360 Cool Down
Before you try anything else, power your Xbox 360 down and leave it turned off for at least one hour. Any time you've been playing for more than two hours, your console will start to build up a lot of heat, and when the two flashing red lights appear on the left side of the Power button, you need to power your Xbox 360 console down before the heat starts to melt and damage the console's internal components, which triggers the three flashing red lights, known as the Red Rings of Death. After letting the console cool down for one hour, you should be able to power it back on without an issue and resume playing for no more than a couple of hours before letting it cool down again.
Unblock Xbox 360 Vents and Remove Clutter
The most common cause of the two red lights flashing on the left side of the Power button is the vents being blocked because the console or power supply is located in a cluttered area. Ideally, leave at least three inches of breathing space on each side of the Xbox 360 console and the power supply that's exposed so the devices can breathe. If the Xbox 360 console is laying horizontally and the front of the console is facing you, the vents are located on the left and right sides of the top of the console, and along the back. The vents on the power supply are located on the side of the power supply where the AC power cable connects. If you do have to house the Xbox 360 console or power supply in a tighter-than-ideal space, make sure that these vents are not covered and can breathe. Also, don't place the Xbox 360 console on top of or below another device that generates a lot of heat, such as a stereo receiver. If both of these devices are turned on, the heat from the other device can cause the Xbox 360 console to overheat faster than it traditionally would. Additionally, don't place the Xbox 360 console on a soft surface that it can sink in to, such as a pillow; this doesn't allow the bottom of the console to breathe properly and can contribute to overheating. Put your console a flat surface.
Use a Cooling Fan
To prevent your Xbox 360 console from overheating, there are a variety of USB-powered fans you can connect to the console to cool it down while it runs. Most cooling fans built specifically for the Xbox 360 console are designed to connect to the USB port on the back of the console so you can clip the fan to the back of the console. Alternatively, you can also use traditional USB laptop fans and place the cooling fan underneath of the Xbox 360 console.