This document discusses the four main parts of a computer system: hardware, software, data, and users. It defines each part and provides examples. It also describes the basic computer hardware components, including processing devices, memory devices, input/output devices, and storage devices. The document explains that software tells the computer what to do and that there are two main types: system software and application software. It provides operating systems and utilities as examples of system software and Microsoft Word as an example of application software. Finally, it defines computer data and describes the roles of computer users.