Computer Viruses

What is a computer virus?
What does a computer virus do?
How many types of virus are there?
How do viruses spread from one computer to another?
How will I know if my computer has been infected by a virus?
What can I do to protect my computer from being infected by viruses?

What is a computer virus?
A biological virus is an entity which uses the resources of the host to spread and reproduce itself. A computer virus is so named because of similarities in the way it behaves. Put simply, a computer virus is a computer program that infects other computer programs and reproduces itself without the knowledge of the PC user.

What does a computer virus do?
Once a virus has infected a program on your computer, it may spread to other programs. It may or may not damage your files and applications, depending on the nature of the virus.

How many types of virus are there?
It is difficult to ascertain the number of different viruses, as they increase in number every day. Although the number runs into the 1000s,it is important to note that very few existing viruses are widespread.

How do viruses spread from one computer to another?
A virus can enter a computer in a variety of ways. You may start up an executable (program) file from an infected floppy disk, or a file which you have downloaded from the Internet may be infected. In the past, most viruses have infected executable code, but some new strains (like the Microsoft Word Concept virus) infect document files.

How will I know if my computer has been infected by a virus?
The precise symptoms of a virus will vary, depending on what the author of the virus has intended. Non-destructive viruses may display a textual message on your screen, or in the case of the Ambulance virus, a small graphic of an ambulance which crosses your screen. More malicious viruses are often harder to discover. By the time you notice things going wrong, the virus has already gone to work.

What can I do to protect my computer from being infected by viruses?
There are no cast-iron guarantees to ensure that your computer will not become infected with a virus during its lifetime. However, you can take precautionary measures which will, if practised methodically, reduce the opportunity of viruses attacking your machine. Principally, should invest in an anti-virus program. There are many of these available, in both commercial and shareware flavours. If you are considering a shareware version, then do be careful to download a reputable site, like Shareware.com. Viruses have been known to pass themselves off as anti-virus programs! You may also like to check out AVP and Datafellows for further useful information.