Alright kiddo, so a quiet PC is a computer that doesn't make a lot of noise. When you turn on a normal computer, you can hear a loud sound because the fans and other parts are working hard to keep the computer cool. But in a quiet PC, these parts are specially designed to make less noise so that you can work or play games on your computer without being disturbed by the sound.
One way to make a PC quiet is to use quieter components like a quieter power supply, quieter fans and quieter hard drives. Some manufacturers even use special materials like sound absorbing foam to help reduce noise levels.
Another way to reduce noise is to make sure the computer is not working too hard. This means not running too many programs at once or trying to play games that require a lot of power. By keeping the computer running at a lower level, it won't get too hot and will produce less noise.
So, if you want a computer that is quiet when you use it, you can either buy one that is specially designed to be quiet or you can make some changes to your current computer to help reduce the noise it makes.