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Keeping Computer Viruses from Infecting Your Computer

Computer viruses are a constant menace to people who spend a good deal of time on their computer. They can cause your system to slow down, freeze, or otherwise act off kilter. Worms, Trojan horses, and viruses frustrate computer users to the breaking point and it's estimated that they cause many billions of dollars worth of computer damage and lost productivity every year.

Separating out the various types of viruses and worms and Trojan Horses is important to both learning how these tiny bits of malicious code get into our beloved machines and educating us to what we can do to remove them when we get them.

The History of Computer Viruses
Viruses have been with us since the dawn of the computer age and have progressed in sophistication as personal computing has evolved. Viruses require a little help from you in order to get into your computer, but once in there, they can cause catastrophic damage.

In the old days, people sharing floppy disks of data and information among computers spread most viruses. Your business partner would bring by a floppy disc full of important documents to print from your computer, but one little virus from the home computer got dumped right onto your hard drive in the process.

Today's viruses are more likely to be spread by e-mail and peer-to-peer (P2P) file sharing networks like Kazaa, Ares or Limewire. There are a few different types of viruses, such as macroviruses, boot sector viruses and program viruses that can attach themselves to programs and propagate inside your computer. Worms and Trojan horses are descendents of viruses, but they infect your computer even easier and can cause even more damage. A survey conducted by America Online found that a worm or virus infects twenty percent of home computers.

Worms, Trojan Horses and Spam
A worm is a very destructive form of virus because it does not need human help to travel around from computer to computer. Instead, worms take advantage of file or information transport features on your system to get passed around. They are also self replicating.

Worms are spread through file sharing networks like instant messengers, P2P sites, e-mail attachments and worm-infected sites online. Worms can propagate on the home computer and send malicious code out over the network or the Internet, taking up huge amounts of bandwidth and slowing everyone down.

A Trojan horse usually enters a computer from an e-mail or by clicking on desired photos and screensavers. The Trojan horse can hide itself in your computer, so you will never know that while that cascading waterfall screensaver you downloaded is soothing your frazzled nerves, it is also deleting files and programs on your computer.

Viruses are also spread through the annoying e-mails known as "spam." These viruses can infect your computer and then use your system to send more spam.

Infamous Viruses
Some of the more notorious computer viruses include:

• Blaster: This virus hit computers in August 2003 Spread through Internet and network traffic, Blaster infected hundreds of thousands of personal computers and cost up to $10 billion in damage.
   
• Brain: The Brain was the first PC virus. It arrived from Pakistan in January 1986 and infected 360K floppy disks.
  
  
• Melissa: This worm, which struck on March 26, 1999, attacked Microsoft Word and Outlook-based systems. It created $300 million to $600 million in damage.
  
  
• VBS/Loveletter: Better known as the "I Love You" virus, it first appeared in May 2000 and has caused more than $10 billion in damage, mostly for businesses.

Responding to Viruses
The best way to deal with Trojan horses, worms, or other computer viruses is to avoid them as best as you can.

Never open an attachment or click on anything that hasn’t been run through the antivirus software on your computer, unless it comes from known and trusted sources.

Don’t click on any pop-up ads or go to any site if you have the slightest suspicion that you might be opening a malicious file. The next line of defense is running a reputable and up to date antivirus program that screens every e-mail and attachment and scans your computer every day. If you follow these tips, you will develop a sixth sense about avoiding worms, viruses and Trojan horses all together.

If you feel that your computer is already infected, most often characterized by running very slowly, there are a number of free virus scan services on the Internet that will scan your entire hard drive and alert you to most viral infections. You will then need an antivirus program to get rid of the problem; those can be purchased or downloaded for free.

It is impossible for a computer with Internet access to operate for more than a matter of days, if not hours, without being bombarded by all types of devious software and eventually picking one up, so these programs are not an option, they are a necessity. They are as fundamental as electricity in keeping your computer running. Firewalls, which prevent unauthorized access to your computer, are also indispensable tools.

Keep Yourself Informed
In the end, vigilance and common sense will help keep your computer virus problems to a minimum. Considering how much many of us rely on our computers, it is exceedingly wise to educate yourself on all the latest ways to combat the current computer virus threats and prevent them before they allowed to make your computing life miserable.