So, what is a computer?


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So, what is a computer?

A father and child enjoying using a computer together

What's coming up?

A desktop computer is one of the most common types of computer. This kind of computer is also known as a desktop or PC, which is short for personal computer.

In this activity, we're going to look at what a desktop computer can do, the parts of a desktop computer, and what programs are.

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What can a desktop computer do?

You can use a desktop computer to do a range of useful, informative, fun and creative activities. Some of these may include:

  • using the internet
  • playing games, music and videos
  • writing letters
  • selling or shopping online
  • banking.

We'll be walking you through many of those activities in future courses, but for now we're going to provide a basic guide to the parts and operations of a computer.

The parts of a desktop computer: the computer case, screen, keyboard and mouse
A desktop computer with the computer case highlighted in blue

Parts of a desktop computer

We are going to look at the different pieces of equipment that connect together to make a desktop computer. These are the physical parts of a computer, and are often called hardware.

The computer case

The case, or box, contains the circuits and microchips that make up the brains of the desktop computer. All the other parts of a desktop computer connect to this case.

The screen

Also known as the monitor, the screen lets you see what's happening on the computer. Some desktop computers combine the screen with the computer case, or box. In most desktop computers, the monitor needs to connect to mains power.

A desktop computer with the screen highlighted in blue
A desktop computer with the keyboard highlighted in blue

The keyboard

A keyboard lets you type letters, numbers and symbols into the computer.

The mouse

The mouse lets you point to and move items you see on the screen.

A desktop computer with the mouse highlighted in blue
A computer screen showing some program icons

What are programs?

A desktop computer will include programs, or applications (apps for short), that let you do a range of things. Programs may also be called software.

A web browser, for example, is a program that lets you use the internet (we often call this surfing the internet). A word processor program lets you write letters, and a music player program allows your computer to play songs.

There are many types of computer programs, and each does something different. Some programs will come with your computer, while others can be loaded onto your computer as you need them.

How to turn a desktop computer on or off

A desktop computer needs to be plugged into mains power to work.

To turn a desktop computer on or off, you need to press the power button. Look for a button usually with a symbol that looks like a circle with a line through it (as you can see in the picture).

A typical power switch for a computer
A typical desktop computer with the power button on the computer case highlighted in blue

On most desktop computers, the power button will be located on the computer case. If the desktop computer has a separate screen, you will need to turn this on too. Look for a button along the front, edge or back of the screen.

On some desktop computers, a single power button will turn on the computer and the screen at the same time. Look for a power button on the front, back or edge of the screen.

The computer may take a minute or two to start. This is called booting up.

A desktop computer with a single power on button located in the screen and highlighted in blue
A close up of a hand typing on a keyboard


You've come to the the end of the So, what is a computer? activity.

You have learned that a desktop computer is made up of several parts, called hardware, and that it also has programs called software.

You will also have learned the main parts of a computer are the:

  • computer case
  • screen or monitor
  • keyboard
  • mouse.

In the next activity, What is a screen?, we'll take a closer look at this important part of a desktop computer.