Even though any number of reasons can cause a PC to run loudly, the problem usually lies with the heat from the central processing unit, or CPU, which makes the fan work harder and thus begin to operate loudly. Furthermore, dirt sometimes builds up in the CPU fan, causing the fan to overheat. In addition, a PC can also sometimes turn itself off because it overheats.
Freelance technology writer Tim Fisher suggests a few simple troubleshooting techniques that usually solve the problem of an overly loud PC. The first step involves cleaning the CPU fan so that it stops overheating. Using a can of compressed air helps to remove the dirt build-up that gets into the fan area. While cleaning the fan typically helps, sometimes moving the PC to a cooler area also helps to prevent overheating. People who experience the PC automatically shutting off may solve the problem in one of these ways, but others may find that the problem is actually inherent to the power supply fan. In some extreme cases, they may need to replace the power supply fan. Investing in a more powerful fan or an advanced cooling system also helps keep the fan from getting dirty and overheating.