What is a Computer Virus?

This page is OLD (1999) and here only for reference!

( See below for safely testing your anti-virus software right now.)

Here is my "simple" explanation:

Here's an example of a virus (technically called a "worm") that was found in many people's email messages in 1999: The Happy99 Virus. (Opens in a new window.) But it's still making the rounds from one unsuspecting person to every one else in their email address book!

Of course, the only way that a virus can get into your computer is if someone actually places it there. In order to keep viruses out of your computer, yet run new applications, you need to continually be asking yourself, "How Sure am I that this program doesn't contain a virus?" Here are some thoughts to help you decide.

A Special "Lab Session" Insert

Is Your Anti-Virus Program Functioning Correctly?

A Safe and Officially Approved Way to Test It:

Give it a check-up right now by using the EICAR (European Institute for Computer Anti-Virus Research) Standard Anti-Virus Test File [ ¹ ]. This non-virus .COM file is completely safe since it was designed by EICAR to simply test that an anti-virus program is working; most of the recent anti-virus software packages recognize it. If yours does not, it simply prints out its name.

When you either: You may first wish to create the file yourself, by :
  1. Copying the string of 68 characters found below these 3 steps (beginning with " X5O " which is a capital "O"; not a zero, and ending with " +H* ") into a text editor,
  2. Saving it as, EICAR.TXT, and then
  3. Changing (re-naming) the file's extension to make the EICAR.COM file.
    ( In some cases, your anti-virus software will do nothing until you actually try to execute the newly created .COM program or scan your hard drive again. In other cases, it may alert as soon as you try changing the extension name from .TXT to .COM; which means that your anti-virus software must be "running in the background" constantly protecting you against the files it was programmed to identify.)


Did your program ALERT you to the presence of the EICAR Test virus?

If not, you would see a window similar to this on your screen:
The result of running the EIRCAR program with no anti-virus alert.

Now try downloading the test file within a ZIP compressed archive:
Download Eicar.zip now.

Does your software ALERT you when it is downloading?

Or, did you need to try extracting (un-zipping) the file first?
Here are all the details of EICAR's Standard Anti-Virus Test File.

To go back to the "Lab Session" above, click here.


SARC's "Virus Expert Training Program"

I used to have links here to four programmed instruction modules with questions and answers from Symantec that taught such things as: What is a Computer Virus, and Related Terms; The Infection Process; and how to handle and Remove viruses... Alas, it's very difficult these days to find any information that a greedy co. figures they can get paid for providing instead. These files were just INTRODUCTORY material (not the full course), but even they are no longer available from Symantec!

Links to other Virus Information Sites:

The Original J and A Computer Virus Information Page - This has almost all the references you would ever need for learning about viruses, and some you shouldn't visit! May be overwhelming in places for novices. (Caution: One section, which is labeled, contains links to sites which may contain live viruses!)

The Starman's Virus Warnings and Hoaxes Page. [Link may no longer exist.]

You can write to me using this: online reply form. (It opens in a new window.)

Back to The Starman's Realm Index Page.

Online since July 26, 1998.



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