A computer virus is defined as “a program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes.” In essence, a virus is an uninvited intruder to your computer system that has one of two purposes: to be a nuisance or to be destructive.
All computer viruses are man-made. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems.
Since 1987, when a virus infected ARPANET, a large network used by the Defense Department and many universities, many antivirus programs have become available. These programs periodically check your computer system for the best-known types of viruses.
Some people distinguish between general viruses and worms. A worm is a special type of virus that can replicate itself and use memory, but cannot attach itself to other programs. A worm usually performs malicious actions, such as using up the computer’s resources and possibly shutting the system down.
A type of program that is often confused with viruses is a ‘trojan horse’ program. This is not a virus, but simply a program (often harmful) that pretends to be something else. For example, you might download what you think is a new game; but when you run it, it deletes files on your hard drive. Or the third time you start the game, the program e-mails your saved passwords to another person.
Note: simply downloading a file to your computer won’t activate a virus or Trojan horse; you have to execute the code in the file to trigger it. This could mean running a program file, or opening a Word/Excel document in a program (such as Word or Excel) that can execute any macros in the document.
Most e-mail is strictly text oriented. There should be little reason to worry about getting a virus through a text-only e-mail. But, if the e-mail contains a file attachment, then the possibility is there that the attached file may contain a virus.
The best thing to do is to treat any file attachments that might contain executable code as carefully as you would any other new files: save the attachment to disk and then check it with an up-to-date virus scanner before opening the file.
Other than being so familiar with your personal computer that you will be able to notice when it is behaving in a strange manner or that it seems to have become sluggish, the only way to tell if you have a virus is through the use of a virus detection program.
Virus detection programs use an existing database of virus patterns called a “virus definition file” to search your personal computer for viruses. By comparing the information on your computer’s disk to the virus definition examples, the virus detection program is able to detect portions of data that match certain virus patterns.
Once the virus pattern has been determined, the virus detection program (also referred to as anti-virus software) will let you know that a potential virus has been discovered. You will then be given the opportunity to delete the virus. In most instances, this simply involves clicking a button on the screen that will tell the anti-virus software to delete the offending file.
There are several ways of practicing safe computing. The absolute first rule should be for you to ensure that there is virus detection software running on your computer. The second rule should be that you should ensure that the virus definition files are current. These virus definition files may be downloaded from most virus detection software companies. The definition files are updated as new viruses are discovered.
Also, should be to never trust the integrity of the data on any disk or program file that you are given. Always check the files on a floppy diskette that someone has given you with a virus detector. And never trust any files that you have downloaded off of the Internet without first running them through a virus detection program.
Lastly, never take it for granted that your files are clear of viruses. Most virus detection software has the ability to do a thorough scan of your local disks at a predetermined time. This means that you can perform a complete virus scan on your computer in the evening while you are sleeping.
No. By following the simple suggestions above, you should be able to safely download files and read e-mail with little or no worry about receiving a virus. Install anti-virus software from a well-known, reputable company, UPDATE it regularly, and USE it regularly.
Please check out the following web sites for more information regarding virus threats and anti-virus software:
Online Virus Scanners
These programs will scan your computer via their website and alert you to any possible virus infections on your computer.
For further information on computer virus resources, please check out: