Active cooling is the most common method used for cooling desktop computers. It involves the use of fans and heatsinks to dissipate heat generated by the computer's components, particularly the CPU. Active cooling systems are designed to pull warm air away from the processor and other crucial components, then expel it from the chassis to maintain optimal operating temperatures.
Reference: Knowledge of different cooling methods is part of basic hardware education, typically included in CompTIA IT Fundamentals and A+ curriculum.