By Bill Grogg

It is estimated by the ICSA (formerly NCSA) in their Computer Virus Prevalence Survey (conducted in mid-March 1996) that if just 30% of the world's PCs used recent, full-time virus protection that the world-wide virus problem would be virtually eliminated.

Virus prevention begins with you. Knowing how viruses spread (see How Viruses Spread) can help us to determine what to do to prevent that spread.

First of all, if you don't presently have anti-virus software, get at least one of the leading products (see Selecting Anti-Virus Products and Purchasing Anti-Virus Software).

Next, scan your system with the anti-virus scanner. It is preferable to have booted from a known clean boot disk (which should be write-protected to prevent the possibility of it ever becoming infected with a boot sector virus).

It is also important to run a full-time, real-time anti-virus protection feature. In DOS, these are terminate-and-stay-resident programs, or TSRs. In Windows, Windows 95, Windows 98, Windows NT, Windows ME, Windows 2000, and Windows XP these are usually in the form of virtual device drivers, or VxDs. These full-time protection programs scan all programs as they are run on your system, files as they are accessed, and boot sectors of floppy disks as the disks are accessed.

As an extra protection measure to guard against boot sector viruses, you may want to set up your machine so that it tries to boot from the hard disk first, ignoring any floppy disk that may be in the system. This isn't possible on all computers, but many of the BIOS chips manufactured in the last few years support this feature. (Of course, when needing to boot from a clean boot disk for scanning or repair, you will need to reverse this setting in the BIOS.)

Since the virus landscape changes daily with the ever-increasing number of viruses being released, it is important to keep your anti-virus software up-to-date with the latest virus signatures, detection, and cleaning methods. Anti-virus software vendors release periodic upgrades to their products and it is a good idea to obtain these when available. Additionally, the good vendors also make available free incremental updates to their products' detection range by posting signature updates as often as weekly on their web sites (see Updating Your Anti-Virus Software), BBSs, and many of the popular on-line services. These updates may also be available on disk via a subscription.

We know that viruses spread through document files, executable files, and boot sectors of floppy disks, so any of these you obtain should be scanned with your anti-virus software before use. If you loan a disk to someone, scan it when it has been returned to you. When you receive attachments with e-mail, scan the attachments after extracting them, but before use.

Since we'd like to completely eliminate the threat of viruses, spread the word and get your friends, coworkers, and companies to start implementing virus prevention methods themselves. The more people who do this, the less likely it will be for viruses to spread.