A personal computer (PC) is a small computer made more common by a system developed by a company called IBM. PCs usually operate using a system of software known as Windows, by a company called Microsoft Corporation. PCs made by a company called Apple Inc. operate using their own system of software called Mac OS X. There is also a free set of software for everybody to get, called Linux. Most people use Ubuntu-Linux, because it is easy to use.

A computer user usually works with a mouse and keyboard to interact with the computer (giving it input), and looks at information (output) through a monitor, often a flat LCD screen or a CRT (a cathode ray tube) much like those used in most televisions.

PCs (and almost any other computer) usually use processors (which handle information given by the user) of brands such as Intel (makers of the Pentium processor) and AMD (or Advanced Micro Devices). Sometimes they may have two processors.

They have a memory, or RAM (random access memory), for moving information (or data) quickly to and from the processor, a hard drive for holding the data after a computer has been turned off, and usually a floppy drive and a CD-ROM drive for reading and writing data. Flash drives and DVD drives may also be used to read and store data. Computers often have a modem which sends and receives data over a phone line, or will use a network to do the same. Computers also have spaces (or ports) for serial devices such as joysticks, and a fast port called a USB port.

Computers may be used for work, including doing math quickly, or keeping records; communicating, with online message systems (such as AIM) and e-mail with people across the world; and fun, such as by playing computer games.