Viruses and the Internet


It is a common misunderstanding of new users of the Internet about how viruses can be spread and attack a computer using the Internet. First, let us establish (for purposes of this document) a definition of what exactly a virus is: A virus is a piece of code that infects your computer without your knowledge. A virus can EITHER be damaging OR non-damaging. In fact, in a majority of the cases, most viruses are non-damaging, simply replicating themselves throughout any systems they have been installed on.

There are several key associated terms used when people discuss viruses:

  • TROJANS - These are viruses that are disguised as something else, for example, a game you have been sent from a “friend”.
  • WORMS - This is just a term used to describe a virus that “worms” it's way through all systems it can (typically on a network like the Internet). Sometimes worms can lead to damage even though they themselves may not contain damaging code since the very act of rapid self-replication can cause computers and networks to be overwelmed with the amount of processing they are being asked to do.


Since a virus must actually “do” something in order for it to infect your computer it MUST be in the form of an “executable” that is understandable to your computer. An “executable” can be a computer program (for example, a “macro” – Word uses these) that is understood by your computer (in the case of a Word macro virus – if you do not have Word you cannot be infected) OR an actual executable (a program directly executed by the operating system, like the Microsoft Word program itself). Often viruses, once executed, will exploit “holes” in the security inherent in most commercial software to carry out what they have been created to do.

In recent years, many features have been added to web pages and e-mail programs that provide the ability to actually “execute” programs when you simply receive an e-mail message or view a web page (a common term used is “scripting” – the mail program has the ability to execute “scripts” as soon as a mail message is read). This feature has been added to support much of the “multi-media” aspect of electronic mail and web pages. The makers of web browsers and e-mail programs have attempted to ensure that any such “scripts” do not damage your system by imposing limits on what they can do to your computer (for example, not being able to write to your computer's disks). These limits are not always 100% secure – recently Microsoft distributed a patch to Internet Explorer that eliminates several holes that were exploited when users visited infected web sites allowing the sites the ability to damage the user's computer. Having said this, it is EXTREMELY rare that a web site would contain a script that would allow it to damage your computer – it is most likely such a site would be far from the main-stream (for example, pornography sites recently).

The ONLY way you can be infected is if virus code is executed on your computer.

E-Mail and the Internet

When receiving an e-mail the easiest way to ensure that you cannot get a virus is to ensure that all “scripting” is disabled (set the security options within the e-mail program to NOT automatically execute any scripts attached to the e-mail) and to NOT simply run any attachments you have been sent (by friends or otherwise – Recent viruses have been distributing themselves by sending themselves to everyone in your contact list so when receiving it you would think it was from a friend).

There are attachments you can be sent that are pretty much guaranteed to be free from any possibility of virus infection. If you are sent a standard picture (such as a JPEG or GIF), for example, it is NOT possible to get a virus since most graphics formats do not provide the facility to execute code on your computer – those formats that DO provide this ability you are most likely not to have installed (EXTREMELY unusual high-end graphics programs) and people would not likely go to the bother of writing a virus for them anyway.

Anti-Virus Programs

There are many anti-virus programs available though it should be understood that the very nature of viruses means that they continually adapt so purchasing an anti-virus program must go hand-in-hand with continually updating it so that you are protected from the “latest and greatest” viruses. Most modern anti-virus packages will offer free updates for a year or so, but this should be checked. Note: Having an anti-virus program does NOT guarantee you will not be infected. Additionally, having an “out of date” anti-virus program can be more dangerous than having no such program at all since it may give you an air of complacency about being infected.

For the PC there are several well-known and trusted anti-virus program manufacturer's including Norton (Norton's Anti-Virus) and McAfee (McAfee Scan and Clean). Note: Norton also has a VERY exhaustive web page about viruses and the latest information available to fight them at


It is possible that no matter how careful you are, you may become infected. This is NOT the end of the world. Only in EXTREMELY rare situations do infections result in loss of ANY computer information or files. Most viruses can be removed by any modern anti-virus program with little, if any, loss of information. If the program cannot remove the virus itself it will provide information on how you can go about doing it (as a last resort reinstalling the operating system and applications from original CDs).


A few guidelines:

  • Always question the source of any program you are going to execute. If you got it from the Microsoft web site, you would most likely be more trusting of that then something you received by e-mail from someone you do not know. Personally, I NEVER execute a PROGRAM sent to me via e-mail.
  • Keep a back-up of any CRITICAL information you cannot re-create such as financial records on a SECONDARY media (like a floppy disk, computer tape or CD). Operating systems and programs can always be re-installed from their installation disks but the novel you have been writing for the past five years can't be. Note: Once backed up (for example to floppy) write-protect the media and store in a safe place – preventing any virus from ever infecting it (assuming you have not already been infected).
  • Try to keep up to date with all patches to your software – particularly your web browser and e-mail programs (regularly checking the appropriate web sites). If there is a well known problem with any of your programs that can be exploited by a virus most likely only a short period of time will follow before a patch is available to remove the “hole”.
  • Perform regular virus scans of your computer (“regular” depends on how much you use your computer – for example, once a week if you use it every day, once a month if you use it only infrequently). There are even web pages now from reputable sources that will scan your computer for you without having to have a program installed on your computer to do this. ANY virus scanner must be kept up to date with the latest virus information since viruses change all the time.
  • Do NOT let the fear of viruses prevent you from enjoying the technology. It is only a SMALL portion of the population that are actually seeking out ways of damaging your computer so don't let the fear of damage effect how you use your computer.