Why the computer is buzzing
At you the cooler buzzes either on the processor, or on the video card, it can on the power supply unit or in the case, if it is additionally installed. Usually this problem occurs after 1-2 years of computer operation. Usually if the PC is not expensive, then after this time the cooler starts to buzz, this is normal. You need to service, or find someone who is setting up or maintaining computers. He will grease you or replace them, they are not expensive. It's best to do everything in advance so that something does not burn.