First, turn off the power to your computer.
Use a wet or dry duster to remove dust from the vents on the back of your PC. Gently lift up any cables plugged into ports on the rear panel–and then use compressed air to remove loose dust around those cables and vents. Give some thought, however, before using canned air with a propellant that can damage sensitive components inside your PC. Avoid using conventional household cleaners that contain ammonia or alcohol near electronics as these chemicals are harmful over time.