How to Use Antivirus Software

Once you find a piece of antivirus software that you like and install it on your computer, there are certain things that you should know how to do with it in order to help it keep your computer safe.  These include enabling real-time scanning for threats, manually scanning for threats, dealing with any viruses or other bad programs your antivirus software finds, and updating the list of malicious programs that your antivirus software can detect.  

It's important to note that most antivirus sofware solutions offer similar features, including those we suggested in our Best Antivirus Software tutorial:

We'll explain these actions, and along the way, we'll also offer a few other tips and tricks that you can use to help keep your antivirus software — and, by extension, the rest of your computer — running smoothly.

Real-time scanning

One of the most important things that you should know how to do with your antivirus software is enable real-time scanning.  It may be referred to in slightly different ways, depending on which brand of antivirus software you use (such as "dynamic scanning", "real-time protection", "dynamic protection", "automatic scanning", "automatic protection", and so on).  However, the general point is that, by having this feature enabled, your antivirus software will be instructed to quickly scan any new file that it encounters from your computer (and, on many newer antivirus programs, the Internet), and block it or otherwise deal with it if it's a virus or spyware.

There is usually a setting in your antivirus program's interface (or one of its menus) that will let you switch real-time scanning on or off.  Generally, it's a good idea to leave it on.

Disabling real-time scanning

Note that there may be times when you have to switch real-time scanning off.  Your computer, a program on your computer, or a website may notify you that your antivirus software's real-time scanning ability is interfering with a download or other update.  Many trusted processes and programs will be able to do this automatically and discreetly, and then turn real-time scanning back on when they're done.

In the event that you are asked to turn real-time scanning off manually, start by using some of our other Internet safety tips to determine if the program or website asking you to shut off real-time scanning is trustworthy.  If the request comes from a program on your computer, you may want to run a manual virus scan on it and its related computer files (see the "Manual Scans" section below), just so you know that a virus isn't waiting to pop out when real-time scanning is turned off.  And if you do decide to go ahead with the operation that requires you to turn real-time scanning off, remember to turn real-time scanning back on immediately after the operation is done.

Manual scans

If you think that your computer is acting strangely and real-time scanning isn't picking anything up, most antivirus software will allow you to perform a manual scan.  Usually, there will be a button on your antivirus software's interface (or an option in one of its menus) that will allow you to start a manual scan with default settings.

In addition, many antivirus programs will allow you to conduct custom scans that check only certain files or folders, only certain hard drive sectors, or even hidden files and folders on your computer that you don't usually use and that viruses don't usually target.

Many antivirus programs will even allow you to schedule custom scans to happen at certain times on certain days.  Just remember to have your computer on at the time you set the scan to run (though certain antivirus software will just run a scan the next time your computer starts)!

Removing threats

If, at the end of a manual scan, your antivirus software detects a virus or other malware program — or your real-time scanner detects one — it will often present you with a choice as to what you want to do about it.

You will usually have a choice of three options:

  • If the threat is relatively minor, you can usually heal the infected file by removing the virus, and perhaps repairing any code in the infected file that has sustained minor damage.

  • You must delete some stand-alone threats (such as spyware or adware), as well as some files that have been infected by stronger viruses and are damaged beyond repair.

  • There are some viruses and other threats that your antivirus software may not know how to deal with yet.  For example, it may not know how to heal or delete the virus because it doesn't recognize the type of threat it is, or it can't get into the file that the virus has infected in order to heal or delete it.  In these cases, you can sometimes quarantine the affected files to keep the damage from spreading.  From there, you can look for advanced virus removal tools on the Internet, or contact your antivirus software provider and see if they can help.

Updating your antivirus software

Along with enabling real-time scanning, one of the other really important things that you can do to get the best use out of your antivirus software is to make sure that it's updated with the latest list of threats.  The more threats that your antivirus software knows about, the more it can block and fix, and the better it gets at guessing what new files it encounters might be viruses or malware (through heuristic detection).

There is usually a button or menu option in most antivirus software interfaces that allows you to update the program or its virus list on demand.

Also, just like how you can schedule scans with most modern antivirus software, you will also often have the ability to schedule updates for an antivirus program or its virus list at certain times on certain days.  Some will even automatically update once their parent company makes a new virus list or program update available.  We highly recommend that you enable automatic or scheduled updates on your antivirus software, if you are able to do so.

Updates of paid antivirus software

If you are using antivirus software that requires a paid subscription to use, make sure to have your subscription set up so that it renews itself automatically.  Or, if this isn't possible, pay attention to notices you receive on when your paid subscription is about to expire, and be sure to take the steps necessary to renew your subscription.  If you allow your paid subscription to lapse, don't panic; this won't result in your antivirus software being deleted or turned off until you start paying again, so you'll still be protected somewhat.  However, you won't be able to receive new updates from the parent company, which could put your computer at risk against new viruses and malicious programs that your antivirus software doesn't know how to detect yet.

One last tip: switching antivirus software

If you don't like the current antivirus software that you're using, you can always switch to a different brand.  However, be sure to uninstall your current antivirus software before you install the new program (though, if you're getting it off the Internet, go ahead and download it first so that you won't risk getting a virus while you have no antivirus software protecting your computer).  There are two reasons for this.  One is that having two programs on your computer doing virtually the same job needlessly takes up memory space and processing power, which slows your computer down.  The other is that certain antivirus programs might actually interfere with each other, with one thinking that the other is a virus itself!

Also, if you're switching away from antivirus software that requires a paid subscription, be sure to cancel your subscription after you've uninstalled the software.  After all, you don't want to be paying for a program that you're not actually using!


Well, that's about everything you need to know in order to keep your computer safe with antivirus software!

Best Antivirus Software

We’ve explained why antivirus software is important for keeping your computer safe while on the Internet, but a question we’re sure that you still have for us is “which piece of antivirus software is right for me?”  Indeed, there are many different options available.  Some of them are free, while others require a paid subscription.  Many give you the choice of free or paid service.  Generally, though, it comes down to the features that you want.  Most free antivirus options will offer good basic protection, while paid subscriptions will offer features such as checking downloads for harmful viruses, automatically identifying and deleting spam and phishing scam emails, and adding an extra layer of protection to your secure online activities.

The following is a list of 5 of the best and most popular antivirus brands.

Top Free Antivirus Software

Avast Software


Named after the nautical term for “stop”, this company based in the Czech Republic is notable for having some of the best free antivirus software around.  In addition to antivirus and antispyware functions, its other features include a web browser add-on to keep Internet programs from tracking your actions, a virtual backup disk for your computer, and even a system that helps you update any program on your computer!  Its paid version has antispam tools and a “firewall” for controlling what programs can access the Internet from your computer, and vice-versa.  But if you don’t mind the advertisements and newsletters in your email, Avast offers great protection for free.



A German-based Internet security company, Avira has some of the best free antivirus software, and its paid antivirus software is good, too.  Avira antivirus software is notable for using cloud computing (see our What is The Cloud article for more on cloud computing) to speed up scans and not take up as much memory or processing power on the computer that it’s installed on.  The free version comes with just antivirus and antispyware capabilities.  The paid upgrade includes an email scanner, network file scanner, an additional web browsing protection system, and a feature that puts notifications on hold when you’re playing a game or watching a movie on your computer.

Best Paid Antivirus Software

Kaspersky Lab


A company formed by Russian computer security expert Eugene Kaspersky (and his ex-wife Natalya), Kaspersky Lab has earned high marks for its antivirus software from independent testers.  Its free programs offer good protection from viruses and malware, and some phishing scams.  Its paid subscription services, however, are what have really garnered attention, offering advanced forms of spyware protection, filtering of spam emails and online advertisements, and a “firewall” that controls the activities and permissions of certain programs.  It has lost marks for its software being somewhat memory-hungry and slowing down computers a bit, but it’s definitely one of the safest options around.

Softwin BitDefender


Based in Romania, BitDefender has some of the best antivirus software out there today.  It’s quick to install, easy to use (with a minimal interface and many “set and forget” functions), and provides good protection against many types of viruses and malware.  Some of its primary features (which may require a paid upgrade) include a spam filter for your email that learns patterns that are common in spam and phishing scams, a virtual environment to test programs for malware-like functions, and continuous monitoring of programs to see if they start acting like viruses or spyware.  Most of BitDefender’s praise has gone towards its paid services, though its free ones are said to be pretty good, too.

Trend Micro


Another trusted name in Internet security, Trend Micro antivirus software includes several computer protection features.  These include virus and spyware scanners and blockers, a hyperlink scanner (to identify hyperlinks that download dangerous files or take you to dangerous websites), an email scanner to block spam and phishing scam attempts, and a system that warns you when you’re about to visit a dangerous website.  The downside is that most of its core options require a paid subscription, but it does offer some free peripheral computer security tools as well.


Consider switching to one of these antivirus programs to better protect your computer today!  Or, if there’s another brand of antivirus software that you trust, then let us know about it.  Above all, stay vigilant and stay safe on the Internet!

For more tutorials about Antivirus software and other important Internet safety topics, check out’s detailed Internet Safety course.

What is Antivirus Software + How Does it Work?

Computer viruses have been around since the earliest days of personal computing in the 1970s.  However, it wasn't until the late 1980s and early 1990s (coincidentally, the time period during which the World Wide Web and commercial Internet were being developed) that computer viruses became more numerous and easy-to-spread, to the point where a whole industry dedicated to stopping them was created.

Several organizations and companies were set up to study computer viruses and how they behave.  They found that, like other computer programs, viruses have a set of predictable elements and behaviours that give them away.  Based on this information, numerous counter-programs were created to identify, block, isolate, and delete computer virus programs.  These counter-programs are collectively known as antivirus software

Over time, antivirus software has advanced to the point where many forms of it can handle not only computer viruses, but also spyware and other malicious programs, including some hacking tricks.  You may hear this new class of antivirus software referred to as "antimalware", but it basically serves the same function.  For the sake of simplicity, throughout these tutorials, we will refer to antivirus and antimalware programs collectively as "antivirus software" (since most modern antivirus software contains both types of programs).

As you will read in our upcoming Best Antivirus Software article, some of the most popular solutions include:

How does antivirus software work?

(NOTE: this information about how antivirus software finds and deletes viruses and other malicious programs is somewhat technical in nature.  We largely put it here just for interest's sake, so don't worry if it doesn't completely make sense to you.)

Antivirus software is generally able to identify and block, isolate, repair, and/or delete virus-infected files using three different detection methods: signature, heuristic, and behavioural.

  • Signature detection involves studying the "digital signature" of a computer virus.  This refers to a part of computer code that uniquely identifies a computer element (such as a program, message, or document).  It's often used in more legitimate online transactions to ensure a user that a message, program, or document has been sent from a trusted person with their consent, and has not been tampered with along the way.  However, many computer viruses use these signatures, too.   This means that antivirus software can check an incoming program's signature against its list of known virus signatures to know if a program contains a virus, and take appropriate action based on the result.

  • Heuristic detection involves a sort of "shortcut" whereby antivirus software will look for certain patterns of code within a computer program and try to match it to patterns of code found in certain computer viruses.  It is often used as a supplement to signature-based detection, which may have trouble detecting new modifications of existing computer viruses.  Heuristic detection may be able to catch these variant viruses by detecting code patterns found in their related "families" of computer viruses, even if the full digital signatures of these variant viruses aren't on the books yet.

  • Behavioural detection involves studying a program's behaviour after it runs to see if it's doing anything bad or not.  For example, a common thing that computer virus programs will do when they are run is copy themselves.  Unfortunately, this style of detection usually means that a program, if it is a virus, will have already caused some damage before it is identified as a virus and neutralized.

    However, there are some advanced behavioural antivirus techniques being developed that will be able to determine whether a program does anything bad by looking at patterns of code within the program itself.  This means that antivirus software won't need a virus program to run in order to know that it's malicious, and it won't need to match external clues like digital signatures in order to know that a program contains a virus.

Well, now that you know a bit about what antivirus programs are, where they came from, and how they work to keep your computer safe, it's time to pick the one that's right for you!