The four main components in a computer are the central processing unit, the random access memory, the motherboard and the hard drive. These components are responsible for a computer's primary functions, including processing software instructions, storing programs and transferring information.

Though the central components are the only parts necessary for a working computer, most desktops and laptops have additional devices that improve operational efficiency. Video cards convert binary data into visible images. Cooling systems are built into computers to prevent overheating and ensure longevity of the system. An adapter is typically necessary to supply enough power for the computer to run properly.