In this lesson, you’ll learn what viruses and worms are, how they can enter your PC, and how you can remove them quickly and easily.
Viruses and worms are computer programs deliberately designed and written to alter the way your computer works, without your permission or knowledge.
A virus has two properties:
- It must be able to run itself.
- It must be able to replicate or duplicate itself.
Some viruses are designed to cause damage to the PC they are on by destroying programs, deleting user files, or reformatting the hard drive, but other viruses are merely prankster programs that spread and present a message in one form or another. But even these joke viruses must be removed because they can consume valuable system resources or cause the computer to crash.
A worm is different than a virus; it is a program that can spread from system to system within another document, such as an e-mail message or a Microsoft Word document.
A Trojan horse is a file that claims to be innocent but harbors malicious code that might do one of a number of different things, such as delete files or steal your data. The main difference between a Trojan horse and a worm or a virus is that a Trojan horse does not replicate itself.
It is quite easy to protect yourself from viruses, worms, and Trojan horses: install a good antivirus program (for example, Norton AntiVirus 2007, McAfee or ZoneAlarm) and keep it up-to-date. A good antivirus scanner will not only be able to detect and block any viruses, worms, or Trojan horses that try to enter you system, it will also be able to remove any malware already installed on your PC.
It is important to keep the antivirus application updated (it’s recommended that you upgrade the main software package yearly) and that you download and install the latest antivirus detection databases regularly, because hundreds of new viruses and worms are released weekly. If you don’t keep the detection databases in the program up-to-date, the app won’t be able to detect and repair anything new that finds its way onto your PC. Consult the help file or manual for your antivirus program to find out how to do this (most are able to update themselves automatically).
Scanning a file using Norton AntiVirus software
Here are a few other precautions you can take to keep yourself safe:
- Be suspicious of any e-mail attachments that you receive from unknown sources. E-mail is the main source of viruses, worms, and Trojan horses.
- Be suspicious of downloads sent to you via chat applications (such as MSN Messenger or AIM).
- Be picky about where you download files from on the Internet; many virus and worm writers use free software to disguise malicious applications.
- Make sure that your PC has all the latest patches and updates installed (if you run Windows, visit the Windows Update site to install all the patches your operating system needs).
- Scan all discs and downloads for viruses before running them.
