The ICT Lounge
Section 8.9:
Computer viruses are self-replicating files that attach themselves to normal files within a computer system.

Once a computer system has been infected, viruses can cause many problems including slowing the computer down or deleting files.

In this section we discuss ways in which virus infection can be prevented.

Key Concepts of this section:
Understand what a computer virus is.
Know how computer viruses can infect computers.
Be able to describe what damage viruses can cause to computers and how to prevent infection.

Computer viruses
Key Words:
Virus, Replicate, Infect, Crash, Pop-Up, Prevention
What is a computer virus?
Viruses are programs that automatically make replicates (copies) of themselves and then attach to other files within the computer.

Viruses infect computers and make them kind of sick.
Viruses can cause your computer to slow down and crash.
Computer viruses can be downloaded from the internet.
Use up-to-date anti-virus software.
Portable storage media should scanned for viruses before being plugged into your computer.
The first computer virus

The first computer virus sent over the internet was created in 1988 by Robert Morris.

Click here for more information.

Any files which have viruses attached to them are said to have been 'infected'.

Once a virus has infected one file, it can spread to others. Pretty soon the whole computer system can become infected.

Computer viruses can cause many problems if they are allowed to infect a computer.

What problems can viruses cause?
Viruses are programmed to carry out different malicious (harmful) functions.

Some effects that viruses can have on infected computers include:
  • Annoying pop-up messages on the screen
  • Clog up the computer so that it slows down and crashes a lot
  • Delete important files or data
  • Access personal data like passwords, bank details or credit card numbers.

How do viruses infect computers?
Viruses can infect computers in many different ways. Some include:
  • Downloading infected files from the internet (especially from illegal sharing websites)
  • Opening email attachments that contain infected files
  • Plugging portable storage media that contains infected files into your computer (USB sticks, CD's, external hard disks etc.).

How can you prevent virus infection?
The best ways to help prevent your computer becoming infected with a virus are outlined in the table below:

Ways to prevent computer viruses:
Use up-to-date anti-virus software.
Use genuine copies of software.
Only open email attachments from people you trust.
Don't allow people to attach portable storage media to your computer with scanning it with anti-virus software first.
Only download software from legitimate websites.

Keeping your anti-virus software up-to-date is very important.

This is because new versions of viruses are being made all the time and if your anti-virus is out of date it won't be able to remove these newer viruses.

Some videos:
Here are some links to videos that contain more information about computer viruses:



Click the above task and answer the questions about computer viruses.


Please add your questions/comments below:

Links to Theory Units:
Links to Practical Units:
Section 11: File Management
Section 12: Images
Section 13: layout
Section 14: Styles
Section 15: Proofing
Section 16: Graphs and Charts
Section 17: Document Production
Section 18: Data Manipulation
Section 19: Presentations
Section 20: Data Analysis
Section 21: Website Authoring