Hardly a day goes by when you don't hear about a computer virus in the news or from someone you know. As a matter of fact, there are well over 8,000 active computer viruses in the world in any given twenty-four period and 5 new viruses are introduced daily. The majority of computers will catch a virus through an e-mail attachment or link. Most viruses will use an infected computers address book to distribute themselves, so you are much more likely to receive a virus from someone you know rather than a total stranger.
However, the best way to identify whether or not any attachment could be a potential virus hazard is by looking at the extension (suffix) of the attached file. Hazardous file attachments are .pif, .exe, .com, .vbs, .bat, .bin, .dot, .reg, .js, .scr, .xlm and .dll. While this list is by no means exhaustive these are the definite ones to be on-guard for. In case you're wondering, catching a virus by file sharing is the second most popular way to get infected. File sharing whether you use removable disks, CDs, DVDs, memory cards/sticks or even synch cables can make your "never connected to the Internet" computer, vulnerable to catching a virus.
Protecting your computer from a computer virus infection is relatively easy if you follow these simple steps:

1. Put anti-virus software on all your computers whether they are Internet connected or not.
2. Don't open or download file attachments (attached files) in your e-mails. Especially the ones with the extensions .pif, .exe, .com, .vbs, .bat, .bin, .dot, .reg, .js, .scr, .xlm and .dll.
3. Don't click on links in the body of your e-mails.
4. Don't download software from web sites that you do not know.
5. Never install software on your computer unless you know where it came from.
6. Run a manual anti-virus scan for every 24 hours you use your computer.
7. Be sure that your anti-virus software is up-to-date. All anti-virus software products usually provide updates every 2 - 4 weeks and this service is free of charge to registered users for up to a year.
8. Received an e-mail from someone you know but didn't expect them to send you a file attachment? Call the person first, before downloading or opening the file attachment to confirm that it really came from them. Some virus programs are very good at making it look like they are just files sent to you from someone in yours or your friends e-mail address book.
9. Put firewall software on all your computers that are temporarily or permanently connected to the Internet.

If you follow these simple steps you should be able to stop a virus before it infects your computer.
About the Author
Dr. Robert Ing is a forensic intelligence specialist and has appeared on North American news networks on the issues of technology crime, computer security, privacy and identity theft. For more articles by Dr. Robert Ing please visit