Woman looking at a giant computer screen that is warning her about a virus
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In a Nutshell: What is a Virus Scanner?

A virus scanner, also known as an antivirus program or antivirus software, ensures that viruses have no chance to harm your device. The internet is full of malware. Antivirus software fights against this malware by constantly scanning your computer for dangerous programs.

It is very important to install a good virus scanner. Pay attention to whether the software is compatible with your device, whether it comes at a good price and whether the program does its job properly. If you are unsure about which program to choose, we are happy to give you some recommendations.

A good antivirus program to try is Bitdefender. This premium antivirus program comes with several options and is one of the best choices on the market.

Do you want to know more about antivirus programs? Read the full article below.

The Internet is a great place to share information or to start conversations, be they political discussions, breaking news, or adorable GIFs of your favorite animals. Unfortunately, there are also many nasty things that await us online. Take, for example, the numerous viruses and other malware hidden in downloads and on websites.

It is important to protect yourself against malware. To do so, the best option is to install a good antivirus program, also called a virus scanner. Do you want to know what a virus scanner does, why you need one, and what to look for when buying one? In this article, we will cover all of these questions and more.

What is Antivirus Software?

Laptop with a bug shielded icon and blob backgroundAn antivirus program is a software program that protects your computer, laptop, tablet, phone, or other internet connected device against malware. Antivirus software, also known as a virus scanner, identifies viruses and subsequently stops and removes them.

Over the years, malware has changed and has grown. Malicious programs have become more diverse, and smarter. Of course, companies that make antivirus software keep up with this change. This is why virus scanners today are sophisticated programs that operate on different levels and in various ways. We will discuss this further later.

Why Do You Need a Virus Scanner?

Computer virus iconBy using an antivirus program, you keep your device safer. Computer viruses – and many other online dangers – are stopped by virus scanners. This greatly reduces the chance that your device will become unusable or your data will fall into the wrong hands.

The internet is full of malware and viruses. This can be, for example, a “normal” computer virus, a computer worm, a trojan, keylogger, or even spywareransomware, or the new and scare threat killware. Once your computer is infected, it is extremely difficult to get your system completely “clean” again. Often, some malicious code still lingers somewhere on your device, even if you have deleted all infected files. As a result, you can never be 100 percent certain that the virus or malware has been completely removed.

To protect yourself against these types of threats, you need a proper virus scanner. Antivirus software scans your files before you open them, so that a virus does not have the opportunity to infect your system. Most advanced virus scanners also detect non-traditional malware. This type of malware does not necessarily need to be “activated” to cause damage, for example, by opening a file. Examples of this type of malware are adware and spyware.

How Does a Virus Scanner Work?

The goal of a virus scanner is to protect your device from viruses and other types of malware. It does this by comparing whatever threat it encounters to a “blacklist”. All viruses known to your antivirus program are on this blacklist.

Infographic showing how does a virus scanner work

As soon as the virus scanner encounters something that has been blacklisted, the program will stop the file and try to delete it. An antivirus program scans your system in various ways:

  • Real-time scans: these scans happen when the antivirus program is running in the background. The software checks every file and every program the minute you click on them. If your virus scanner encounters something suspicious, it will let you know. Because the scan happens before the file is opened, the virus is stopped before it can infect your system, keeping you and your device safe.
  • Scans of your entire system: system scans are done in one go and check your entire device for possible viruses or malware. Full scans are not often necessary, especially when real-time scans are constantly taking place. However, it can be useful to run a system scan when you install a new antivirus program. The weekly scans that many antivirus programs automatically run are also useful because they doublecheck your entire system for the most recent viruses. At any other time, your antivirus software will activate immediately, in real-time, as soon as you click on a file with a hidden virus.

The blacklist

List With Magnifying Glass and Shield SmallWe have already mentioned antivirus programs’ “blacklist”. Many virus scanners work with blacklists. They contain all kinds of “definition files”, which are files that correspond to known viruses. Essentially, a blacklist is, as it were, a sort of database of all viruses known to the virus scanner.

During a scan, antivirus programs instantly compare the files on your computer with the definition files that are on its blacklist. If it finds a match, it means that a virus on the blacklist is in that file on your computer. The virus scanner then goes into action and isolates the dangerous file.

Threat detection

Mobile threats iconIn addition, many antivirus programs also use predictive techniques, also known as “heuristics” or “threat detection”. This enables virus scanners to identify new or modified forms of malware, even if they are not yet on the blacklist.

Furthermore, a virus scanner should be able to detect whether something is wrong when programs behave suspiciously. Take a file, for example, that tries to penetrate other files to overwrite their internal code. A good antivirus program picks up this unusual behavior and counteracts it.

A disadvantage of heuristics is that a prediction can never be 100 percent accurate. It is a prediction after all, and not a certainty as when a virus is on a blacklist “in black and white”. This means that, if a virus is not (yet) on the blacklist, your antivirus program cannot be sure it is a virus. This could lead the virus scanner to draw the wrong conclusion and may identify a safe file as a virus. Therefore, antivirus programs cannot be too “aggressive”. Otherwise, you will just get constant notifications and using your device would become a pain.

Can I Use a Free Antivirus Program?

Antivirus shield icon with the label As with many other types of software, there are both free and paid virus scanners. So yes, you can opt for and download a free antivirus program to protect your computer. But be aware, there is more to it…

Many free programs that claim to be “an antivirus program”, themselves carry malware. Once you download the software, malicious code will enter your computer and can cause you a lot of misery, when all you were trying to do was to protect your device. To avoid this, we recommend that you make sure you are well-informed and, for example, check reliable reviews before you download such antivirus programs.

Other than the fact that some free antivirus programs contain malware, there is another reason to be wary of free virus scanners. Many free antivirus programs are not nearly as good as paid versions. You will need to, for example, check for yourself that your system is always up to date, and you are less well protected in general.

Fortunately, there are a few very good free antivirus programs out there. In this article we will discuss one that you can use safely.

The Difference Between Antivirus Software and a Firewall

Laptop screen with a firewall iconIf you have heard the word “antivirus” before, you will most likely also have heard the word “firewall”. A lot of people think that these are two sides of the same coin, but that is not entirely true. They perform slightly different tasks. Therefore, it is wise to not only install a virus scanner, but also ensure you have a good firewall.

The difference between an antivirus program and a firewall lies in when a malware threat is detected and how it is neutralized. Antivirus programs scan the files on your computer for malware, whereas firewalls protect you from malware, cybercriminals, and other malicious things on the internet before they reach your computer. You can see a firewall literally as a “wall” between yourself and the online world. Only files and information considered safe can pass through the wall. An antivirus scanner, on the other hand, scans all files already on your computer and eliminates them, even if they have not yet been activated.

Many virus scanners do have their own built-in firewall. This means that you install both at once. For more information about firewalls and the difference between firewalls and virus scanners, please read our article “Virus scanners and firewalls: what’s the difference?”

Buying Antivirus Software: What to Look For?

Infographic showing what to look for when buying antivirus software

Getting new software is always difficult, especially when you need to pay for it. How do you know if you are making the right choice? Can you be sure that this virus scanner is better for you than that one? Here are some things you might want to keep in mind when considering which program is the best antivirus software for you.


The most important characteristic of a good antivirus program is, of course, that it does its job properly. Does the program identify the majority of viruses? Can it disarm malware before it affects your computer? These things are difficult to test without installing and working with the software and, actually, you don’t want to test this at all. You just want to know. Fortunately, there are many online reviews from people who have already done the work for you. The antivirus software is carefully tested so that you know what to expect.

Operating system and compatibility

When purchasing software, it is important to check that the program works on your device. Therefore, you should check whether the antivirus program is compatible with your operating system. Whether you have a Windows, Mac, Linux, Android, or iOS device: as long as the virus scanner works with it, you’re good to go.


A software program that is easy to use and easy to navigate makes a difference. A user-friendly interface is a must if you want to easily find your way around the program and uncover the various features. Maybe you want to regularly view a list of all the actions performed by your virus scanner. Maybe you prefer to decide for yourself whether a file is dangerous or not before your virus scanner intervenes. Or, on the contrary, maybe you do not want to notice at all that your virus scanner is running in the background while you are using your device. This has all to do with the user-friendliness of the program and the options available with virus scanner.

Customer service

In addition to the virus scanner’s user-friendliness, you may find good customer service equally important. Have you run into a problem? Is your antivirus software not responding as it should? If that is the case, it can be very helpful to have a support team available that can quickly and efficiently answer your questions and help solve any issues.

Some antivirus software developers offer support, others do not. Of those that offer support, some offer a live chat, while others only offer email support. The latter can increase the waiting period. Be mindful of what you prefer and take this into consideration.

Extra options

Every virus scanner tries to differentiate itself from its competitors. They do this, among other things, by offering extra options. In addition to a virus scanner, they also offer a password manager, for example, or protection against phishing scams. Others offer you cloud backup space when you purchase a subscription, or give you a discount on a VPN service.

In addition to these extra options, the ability to precisely adjust the settings can also make a difference. A novice user probably wants to get started as soon as possible. An advanced and more technical user, on the other hand, will like the benefits manual configuration has to offer.


Of course, the price of your antivirus software is also an important factor. Ideally, you want to protect your devices as optimally as possible without having to pay too much for what you need. You could consider freeware or opt for more security with a paid virus scanner. As we discussed earlier, some free virus scanners work quite well, but they do come with some risks you need to be aware of.


Other people’s opinions and experiences with different antivirus programs are most likely your most useful resource. While you are probably not able to or capable of testing different virus scanners, others are. You can find numerous reviews online.

On Google Play, for example, people often rate the apps they download. Sometimes they include comments, which can be a very useful source of more details. On forums such as Tweakers, technical users discuss the effectiveness of specific virus scanners. This can also be a good resource if you speak some of the lingo. And on official websites like ours you will find well thought-out and complete reviews of the best and most well-known virus scanners. Make smart use of these resources before making your choice. In this way, you will find the best antivirus program for you.

Two Good Antivirus Programs

If you are not sure which virus scanner is the best one for you to purchase, we are happy to be of help. Here are two reliable virus scanners that we confidently recommend. One a paid version and the other a decent free alternative.

Best paid virus scanner: Bitdefender

bitdefender-logoBitdefender offers many different subscription options and has software for both home users and businesses. Their antivirus software ensures that you are well protected against malware. You also get webcam and microphone protection, so that strangers cannot eavesdrop on you.

The software updates automatically, so you do not have to constantly check whether your antivirus software is up to date. Moreover, this virus scanner does not slow down your system. You can try Bitdefender for free for 30 days. Do you want to know more and at the same time receive a substantial discount? Click on the button below.

Visit Bitdefender

Best free virus scanner: Avast Free Antivirus

Avast logo smallAvast Free is Avast’s free version of its virus scanning software. This antivirus software offers good “real-time” protection and threat detection, making it perhaps the best free alternative to premium virus scanners.

More than 400 million people worldwide use Avast. All these computers act as a gigantic network: if a new threat is identified by a user, this information is immediately shared with the entire network.

The disadvantage of this free software are the advertisements. The program constantly tries to convince you to switch to the paid version of Avast.

Visit Avast Free

Getting Started with An Antivirus Program: Step by Step Instructions

Do you want to install antivirus software on your device? This is how you do it quickly and easily:

  1. Choose an antivirus program: to find the best virus scanner do your research. Consider price, compatibility, effectiveness, and any extra options you may want to use.
  2. Download the software: choose a subscription with your preferred provider and download the corresponding software from the provider’s official website.
  3. Run a full scan: put your new antivirus program to work right away. Let the software perform a full system scan, so it can immediately neutralize all viruses that may already be hiding on your device.
  4. Let the software run in the background: the virus scanner will continue to run in the background and intervene when necessary. You can continue browsing with confidence.

Safe Online: What Else Can You Do?

Infographic showing what can you do to stay safe online

A proper virus scanner will protect your device against most types of malware. In this way, it is much less likely that computer viruses, keyloggers, or spyware will become active on your device. However, there are more online risks. So, what else can you do to protect yourself online?


A good firewall blocks most malware from reaching your computer. That is why it is wise to install a decent firewall in addition to a good virus scanner. Windows devices automatically come with a reliable firewall called Windows Defender. You can manage this firewall within Windows Options. Many antivirus programs also have their own firewall that you can use.


If you not only want to use the internet safely but also anonymously, a VPN is a good idea. A VPN (Virtual Private Network) ensures that your IP address remains hidden. This makes it very difficult for other parties, such as hackers and websites, but also your internet provider and housemates, to follow what you are doing online.

Do you want more information about VPNs? You can read here what exactly a VPN does and which are the best VPNs at the moment.

Password manager

Nowadays you need to create a user account on any and every website or platform you want to visit. Furthermore, you need to enter a unique login for each of them. We cannot emphasize enough how important it is to create a strong and unique password for every account, so that others cannot easily guess or crack your passwords. If you find it difficult to remember them all, you are not alone. A password manager offers a perfect solution for this: you simply store all your passwords and accounts in this program. All you need to remember henceforth is your password manager’s password. Just make sure you choose a reliable password manager, such as RememBear or Blur.


It may seem over the top, but nonetheless, we cannot stress enough how important it is to keep all your software and applications up to date. Updates ensure that the latest security holes are patched, and that the latest security information is loaded into your program. This is extra important with virus scanners as new viruses need to be added to the blacklist as soon as possible. But it is also important for other software, as updates fix code weaknesses and bugs. If you ensure that your entire system is up to date, you are a lot safer online.

Common sense

In addition to installing and updating all these layers of protection, it is very important that you are vigilant when online. Make sure you are well informed about the various types of scams, malware and cybercrimes currently active. Know, for example, how to recognize and avoid phishing. If you are well informed, you can navigate more safely on the internet. You are more likely to recognize malicious software, viruses, and scams, making you more secure.

Looking for more tips on how to stay safe online? You will find them in our article “8 Simple Steps to Guarantee you Stay Safe Online”.


Antivirus software helps you to protect your computer against viruses and various types of malware. There are even dedicated gaming antiviruses that balance resources. There are a number of virus scanners on the market to choose from. Some are rather basic and free, while others offer you more options but you need to pay for them. Before you make a choice, it is a good idea to check what is out there and which programs are useful and reliable. You can do this, for example, by reading our reviews.

In addition to a virus scanner, there are more ways you can better protect yourself when online. Consider, for example, the use of a firewall, a VPN, or a password manager. Ideally, you need both a VPN and an antivirus for maximum protection. Either way, an antivirus program is a good first step towards online safety.

What is a Virus Scanner: FAQs

Do you have a question about antivirus programs and how they protect your device? Click on one of our frequently asked questions below to view the answer.

What is Antivirus Software?

An antivirus program identifies malware on your computer and subsequently ensures that this malware, whether a computer virus or worm, for example, is eliminated before it causes any damage. Antivirus programs are also called virus scanners. If you want to properly protect your computer, phone or other device while browsing the internet, an antivirus program is a must.

What is the best antivirus program?

There are paid as well as free antivirus programs. Free is always nice, of course, but paid versions are generally better and/or will most likely better fit your needs. Bitdefender is a great option to protect your devices. Would you rather try out a free option? Then we recommend Avast Free Antivirus.

How does an antivirus program work?

Most virus scanners use a combination of a so-called blacklist and threat detection to protect you against malware. The blacklist is a collection of code that the virus scanner knows to be viruses. If the software encounters this code, the code will be deleted, and the device is safe.

Threat detection is a predictive technique an antivirus program uses to discover suspicious code in newer viruses. However, on some occasions, perfectly safe programs are accidentally labeled as viruses.

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