CPU

The Central Processing Unit (CPU) is the main brain of a computer, it sits on the motherboard. It controls the actions of the computer, performs the basic and complex arithmetic, and controls the input and output operations of the computer. Without a processor the computer, or any device with a processor (most devices if not all), you wouldn't be able to load anything, the operating system wouldn't work and you would be forced to use the BIOS.

The processor has 2 main units, the Control Unit and the Arithmetic Logic Unit

Every computer contains an internal clock, this regulates the rate at which instructions are done. The faster the clock the faster the processor can process commands, instructions etc.

A CPU also has something called Registers. These store everything that is needed in everything calculation by the processor.