Viruses: How do I keep myself safe from viruses?

Install and run an anti-virus program

There are many out there.

From my article What Security Software do you recommend?, the super-short version is to install Microsoft Security Essentials. This is what I currently run on all of my machines.

I also run Malwarebytes Anti Malware periodically. This is what I use when I remove viruses from friends' machines. After some recently pervasive virus infections, it was one of the first to recognize and clean them up. It has also garnered quite a good reputation.

I've run other anti-virus solutions with good results including the free versions of AVG and Avira. I also hear good things about the free version of Avast.

While I'm not a big fan of their product offerings, Symantec maintains one of the best reference sites for virus-related security issues.

Not all virus scanners catch all viruses. I recommend having a selection of additional virus scanners to run as a "second tier". Most downloadable virus scanning solutions often include free trial periods that can also come in handy as one-time, second-level scans.

Whatever it is you choose, download and install the package of your choice.

Now. Before you forget.

Update the anti-virus database

After installing your anti-virus software, your first step should be to update the virus signature database that came with it.

The anti-virus program alone isn't enough. Each uses a database of known viruses to know what to check for and that database needs to be kept up-to-date.

New viruses are being created every day and the databases used by anti-virus programs are being updated that frequently as well. You need to update to the latest database for your program right away.

Most of the programs have update functions that will locate, download, and install the latest databases regularly and automatically.

Make sure that this is enabled.

Run regular scans

Most of the anti-virus programs work automatically. Once installed, they are configured to scan all incoming and outgoing files and often hook into your email in some way to double-check that your received email is clean as well.

Unless you know what you're doing, make sure that this "real-time" scanning is enabled. (There are scenarios where real-time scanning, particularly of email, may cause problems. Unless or until you run into those problems, however, you should leave this enabled.)

I also recommend periodically running scans of your entire hard disk, including all hard disks if you have more than one. Certainly when you first install the software, you should run a full scan. Then, depending on how heavily used your machine is, you should run a scan periodically as well.

Some programs will allow you to schedule such a scan to happen automatically. In my case, for example, my computers are on 24 hours a day, so I schedule full virus scans nightly while I'm asleep.

Keep Windows up-to-date

Visit Windows Update regularly or simply enable the automatic update feature in Windows.

All software has bugs. Some of those bugs result in vulnerabilities that are then exploited by malware writers to create viruses that can infect your system. As these bugs are found, Microsoft fixes the affected components in the operating system, eliminating the vulnerabilities, and makes those fixes available for download and automatic installation using Windows Update.

The "problem" is that once the bugs are discovered and publicized and even when the fix is available, virus writers get busy writing viruses that still exploit them. Why? Because they know not everyone stays up-to-date.

Don't be one of those people.

Keep Windows up-to-date. Let someone else have the "fun" of being infected with the latest viruses. Visit Windows Update weekly or enable automatic update.

Additional notes

There is no "best" anti-virus program.

In fact, any measurement of which are "better" or "worse" changes over time. Each may miss some thing that the others catch. That's one of the reasons why I list several alternative anti-virus programs above. The best advice is to use one, any one, and have the others "on call" for those cases when a virus sneaks past the one program that you use regularly.

If you do install more than one package, you should not enable the "real-time" scanning for more than one at the same time; they will conflict with each other and cause, as they say, "unpredictable results".

(This is an update to an article originally published April 24, 2005, and updated on October 6th, 2010.)