Like everything else in your home, your computer collects dust and debris. As this builds up, your computer's cooling system becomes less efficient, leading to a hotter system. To make matters worse, dust can clog up your computer's fans and prevent them from spinning freely at full speed. Technology website CNET suggests cleaning your computer with compressed air every six to 12 months.
Turn your computer off and unplug everything from the tower. Open the computer case to reveal the inner components. With your can of compressed air, blow dusty components in short bursts, keeping the can about an inch from where you're aiming. From the inside, blow the air over vents to push out dust they've collected. When blowing your computer's fans, place a finger on a fan blade to keep the fan still as you clean it.
Since laptops are typically much more difficult to disassemble than desktops, you may not be able to clean your components as well. Shoot the compressed air at the laptop's vents. If you feel comfortable taking your laptop apart, you'll get better access to internal components.