What is A Computer Virus?

"A parasitic program written intentionally to enter a computer without the user's permission or knowledge. The word parasitic is used because a virus attaches to files or boot sectors and replicates itself, thus continuing to spread. Though some viruses do little but replicate, others can cause serious damage or affect program and system performance. A virus should never be assumed harmless and left on a system." -- Symantec

Computer viruses are intriguing and get our attention. However, viruses show us how vulnerable we are. A properly programed virus can have an incredible effect on the world wide web. They show how advanced and interconnected humans have become.

For example, the virus which made the news world-wide is the Mydoom worm, which experts estimate infected approximately 250,000 computers in a single day (Times Online). Back in March 1999, the Melissa virus was so powerful that it forced Microsoft and a number of other very large corporate entities to completely turn off their e-mail servers until the virus could be contained. The ILOVEYOU virus in 2000 was also very devastating. That's very impressive when you realize that the Melissa and ILOVEYOU viruses are extremely simple.

If you dont understand a term in this section, have a look at this Virus glossary.
Follow this link to get some Virus Detection and Prevention Tips and tricks.
By now you should be convinced that an anti-virus program is a must. Follow this link for a list of free and not so free anti-virus software.