One of the most troubling aspects of using a computer today is the risk of viruses, worms, and Trojan horses. A virus is a computer program that is designed to spread itself from one file to another on a single computer. A virus will not intentionally spread itself to another computer. That’s where we come in. By sending an e-mail with an infected attachment, the virus is sent to an unsuspecting user without your knowledge.
Worms are also computer programs, but unlike viruses, do not need human interaction in order to spread. The computer worm is designed to copy itself from one computer to another via E-mail. Once the worm has infected your computer, it will use your address book to send anonymous E-mails, with the worm attached, to everyone that is in your address book.
A Trojan horse is a program that appears to serve some useful purpose, but hidden within is a destructive program, virus, or worm. For example, last November, a Trojan named Trojan.Zasil was spread via E-mail with the subject “free video”. The Trojan can do no harm unless it is opened or launched.
The best protection from these destructive programs is to install antivirus software on your computer. Most computers that you buy today will have this software already installed. The software is relatively inexpensive, and there are numerous reputable companies that provide it. It is most important to not only use the antivirus software regularly, but to also update it. New viruses come out daily, and the antivirus companies send out updates as soon as they can. Renewing the yearly license is critical to the virus updates. Once the license expires, the virus scan will still run, but there will be no protection from any new viruses. Some of the worms that have been released actually disable antivirus software, or prevent you from even installing the software. There are ways around this; however, the risk of losing critical files increases significantly.
A virus, worm, or Trojan horse can cause your computer to act differently. You may notice a significant speed decrease, or as the destruction spreads, it may cause programs to work improperly or even stall your computer. In some cases, you may even notice that the hard drive sounds different.