This video explains the different components of a computer and their roles. The processor is the main component responsible for the computer's functions, and RAM serves as a buffer between the processor and storage. The motherboard connects all the components, including the power supply and cooling system, and includes a platform controller hub (PCH). Graphics are generated using a graphics processing unit (GPU). The GPU connects to the motherboard using PCI-Express slots and contains its own RAM and modulator. The motherboard also includes components for sound, networking, expansion, and fan control. The video provides a diagram showing the main components of a computer.