History of

• Computer viruses actually predate the Internet. The first computer virus was the Creeper virus, which infected computers using the TENEX operating system connected through the ARPANET. Early viruses were spread through floppy disks because computer networking was not popular yet. However, the Internet has become a breeding ground for viruses with new and more devious techniques being put into play to get people to download infected files.
  
  

Type

• While computer viruses are all destructive to the computers that they infect, the way that they spread tends to differ. Macro viruses are embedded into documents that can be opened by programs like Microsoft Word, activating the virus as soon as the user opens the file. Some URLs automatically download harmful files when you click a link to them; these are direct action viruses that are often sent via email. Resident viruses find their way into RAM memory and begin corrupting all programs and files. Popular sites like MySpace have fallen victim to cross-site scripting viruses that infect otherwise harmless websites.
  
  

Risk Factors

• Because of the nature of computer viruses, they can be extremely harmful to your computer. If you do not have updated antivirus software, you are much more vulnerable to viruses that can infect your computer. In addition to slowing down your browser, viruses can also delete important files, ranging from core system files to the pictures that you store on your computer.
  
  

Effects

• When your computer is infected by a virus, any of a variety of things can happen. Some viruses display a series of messages on the computer screen that keep popping up when the user tries to close them, taunting the user for downloading the virus. Other viruses aim to make your computer inoperable by getting rid of necessary system files, making you spend plenty of money getting your computer repaired and possibly causing you to lose all of your data.
  
  

Significance

• Computer viruses, as well as other harmful applications that travel throughout the Internet, have made the Internet a rather unsafe place for unprotected computers. Because of the sheer amount of computer viruses out there and the speed at which they can spread, viruses have added a dimension of apprehension and worry to those who rely on computers for their livelihood. When purchasing a computer, be sure it is equipped with antivirus protection. Top antivirus software includes AVG, BitDefender, Kapersky, Norton and Shield Deluxe. You should also use anti-spyware software, such as Ad-Aware, to keep your computer free of problems.