5. Computer Viruses and Malware

A Computer Virus is a computer program that is designed to copy itself repeatedly and attach itself to other computer programs.

In the early days of personal computing (1980's) some of the people who created them did it as a 'joke'.

For example, there was a virus that caused all the characters on screen to drop into a heap at the bottom of the display. Very annoying, but relatively harmless.

However, quite soon some really nasty versions came out that were deliberately designed to corrupt and delete your files as well as trying to copy itself everywhere.

Viruses can cause an immense amount of time wasting and financial loss for people and businesses.