A computer virus is a piece of software that gains access to your computer and there replicates itself. From there it is able to spread and infect other computers that yours is linked to.
A common misconception about viruses is that they infect the actual hardware of the computer. This is not true; viruses only infect the software that is on the computer. Another misconception is that viruses are all designed to be destructive. Again, this is not true. Some viruses only display a message or sign, others cannot even be detected by the average computer user, the only sign they are in the computer is that the system is slower than usual as the virus uses memory and power to replicate itself.
While many viruses are not harmful, merely rather frustrating, others can damage and even destroy your computer. Some viruses can even destroy entire networks, or shut down the computers of entire companies. Examples include the Melissa virus, according to HowStuffWorks, in March 1999 this virus forced the shut down of many large company's e-mail systems, or the CIH virus which according to ChannelWeb caused 20-80 billion dollars damage worldwide.
In the days before the internet was widespread, viruses were mainly spread on floppy discs. This was because floppy discs were the way people were able to share information, and so if a virus got onto one of these discs it would quickly spread to the computers of all the people who used the disc, and from there onto the discs they write to from their computers and then further onto the computers that used those new discs... And so on and so on and so on.
Nowadays with the way internet is used for sharing so much information, viruses are mainly spread online. They can be hidden inside files attached to e-mails, or hidden inside programs you download.
There are ways to protect yourself against viruses however. Antivirus programs such as Norton's, and AVG can be installed to detect and destroy any viruses that are found either on your computer or in discs you use with your computer. These programs rely on connection to the internet in order to download updates that tell them about the newest viruses and how to destroy them. In this day and age when viruses can be so dangerous to your computer, installing antivirus software and allowing it to update often is an absolute necessity.
In this day and age, where so much of our important information is held digitally, it is vital that we understand what viruses are and how to prevent them.
