There's a fan on top the CPU, one inside the power supply, and usually one or more on the front and/or back of the case.
Enwere onye na-akwado n'elu CPU, otu n'ime ọkụ ọkụ , na otu mgbe ma ọ bụ karịa na n'ihu na / ma ọ bụ azụ nke ikpe ahụ.