This article is based on a NewsGroup posting by "Bluesicle". Thank You!

Remember that viruses are nothing more than programs. They need to be RUN (CLICKED ON, OPENED etc.) Once running, they do their damage by accessing your operating system and altering or deleting some of your files and spreading themselves by accessing your MS OE address book and emailing themselves to all of your contacts.
Even when computer viruses are sent as email attachments, you must open or run them for them to do any damage. If you delete them, you are safe. One of the problems is that people use programs like MS Outlook (+Express) which is usually set to automatically open attachments. This is VERY dangerous. This auto-opening of attachments can be disabled. Or better still choose to use another email program! A search of sites like www.FREEedge.com/ zdnet.com/ or www.Tucows.com will produce alternatives.

The secret of detecting viruses lies in the EXTENSION of the file. That is the very last part of the file name following the last (.) period. This describes what type of file it is and cues your computer on how to treat the file.
Like :
myphoto.JPG - .JPG is the extension and when clicked it would open your photo viewer.
mygraphic.GIF - .GIF is the extension and it would open your graphic viewer.
mymovie.MPG - .MPG is the extension and it would open your movie viewer.

BUT NOTE...
With mymovie.MPG.EXE - .EXE is the extension, not .MPG. The last part is what instructs your computer on how to deal with the file when clicked on.
So this file may have nothing whatever to do with an MPG or movie file. And is probably a virus!!

SO! your best bet is to never click on or run any file, download, or attachment that ends in
.exe
.com
.vbs
.src
or any other unfamiliar ones.
These four are handled by your computer, from the factory, as runnable
programs that will do whatever the virus writer wants. The "I Love You"
virus that went around was .vbs, a very simple program that runs in visual basic, a very simple language.

And be very careful of ones that APPEAR to be innocent, like
*.mpg.exe where they try to make you feel like it is a movie file, but notice the ending extension. It will most likely be bad, and not very original.

This not to say that all files that end like this are bad. If you download software it may very well end in .exe, but if you know it is from a reputable place, it should be OK.
You can use virus checkers to see if a file is a virus, but it is important to keep your anti-virus software UP-TO-DATE!!

**A note about files ending in .zip
These are Zip files, that is, they are usually a compressed file used to save space on a disk or for down-loading speed. They can contain another file, or many files that 'expand' or unzip when you click on it. The files that come out of it will not RUN automatically when you unzip the .zip file, but they could end in any given extension. So you would need to again check the extensions on each of the files that came out of it, and the same rules apply.

Good Anti-Virus software like "InnocutateIT" from Computer Assoc. will check *.ZIP files for viruses two levels deep.

Disclaimer: Any trademarks or trade names used in this article are the property of the respective owners. This web site respects that ownership and any use of these trademarks or names is purely for educational purposes.

Viruses must be written in a LANGUAGE that is a runnable language to be understood by the computer.

These languages are:
.exe - for executable files
.vbs - for visual basic script
.bas - for basic
.com - for companion files (not used for programs much now, but are runnable and are used for very small executable virus programs).
Also be careful with - .bat files and .scr files -
(i.e. screensavers, as they have the potential to contain virus type files as well.)

Be familiar with the files you are opening. For example......
picturename.jpg files are the picture files that you are familiar with. When you click on one, it will be opened by the picture viewer you have on your computer. A *.jpg will not be a virus, because only a picture viewing program will run it, and will not be able to handle any other language code.
That is not to say it could not be named - picturename.jpg.exe (remember the extension location?)

The same with :
.gif
.mpg
.mpeg
.avi
.mp3
and files for Lotus or Excell, .wk4, . xls
and many others

These files will only open with the program that is dedicated to them, and this program in turn can not run executable code language that can be a virus program.

Some extensions that do have a dedicated function, though, can run a program. Like *.scr (screensavers). They can be designed to run any binary program, and if they contain a virus program they can do damage.

Viruses are never sophisticated and never take any brains to do. Anyone out of 8th grade can put together and spread a virus that will do some damage in less than a month.

Think of virus spreaders as the most ignorant and cowardly of all. It would be like a little boy next door picking your prize flower, then waiting until night and sneaking up behind and smacking him over the head with a bat, running away, all with the protection of a mask of course. Anyone who tries to handle things he does not like with a virus, or does it just to be malicious carries a very immature mind, and there is not much you can do. Often they are do-gooders with little ability to do something in the adult world.

For more details on computer viruses, hoaxes and scams pay a visit to:

The Safe Surfing Files

• Up to date details on the latest Virus Warnings and Alerts!

• FREE Anti-Virus and Firewall software!

• FREE monthly newsletter to keep you safe on the Net!

• Details on how to check if your anti-virus and firewall programs are really working!

• Warnings of Internet Scams and Hoaxes!

• Handy Tips on Safer Net Surfing!