Home » Computer Guides » PC Security Guides » How To Use Microsoft Windows Security Anti-Virus.

How To Use Microsoft Windows Security Anti-Virus.

When it comes to anti-virus protection, Microsoft provides a built-in solution in the form of Windows Security.

Formerly known as Windows Defender and Windows Security Centre, it has improved over the years to the point that now, it could really be all protection you need.

Microsoft Windows Security.

To open Windows Security Centre left click the START button and then type “windows security

Left-click WINDOWS SECURITY (App).

Windows Security typed into search box and displayed in serach results in Windows 10.
Launching Security Centre from Windows 10.
Windows 11 start menu open. Windows Security has been typed into search box and is highlighted in results.
Launching Security Centre from Windows 11.

You can also open Windows Security from the hidden icons area on your Taskbar.

Left-click the upward-facing arrow to open the hidden icons. Then left-click the shield icon.

Windows 11 desktop. A red arrow is pointing to the hidden icons arrowhead.
Hidden icons arrowhead on the taskbar.
Windows Security/Defender sheild icon marked in Hidden icons area.
Windows Security shield icon.

The Security At A Glance Page.

When Microsoft Windows Security opens, you’ll be on the “Security At A Glance” window. This page serves as the home page and allows access to all the various components that make up Windows Security.

The very first thing to do is to check that Windows Defender is the active anti-virus program on your computer.

Click VIRUS & THREAT PROTECTION”. Click on the actual title.

If there is a button to “Set Up OneDrive” or “Update”, don’t click that. Click on the actual title.

Virus and protection link is marked.
Virus and threat protection.

Other Security Options.

There are two other security options that you could enable within Windows Security but they both take a little more involved than the scope of this guide.

However if you’d like to review them you can click here Enable Reputation Based Protection In Windows 10 And 11. and Core Isolation Memory Integrity In Windows 10 & 11.

Third Party Anti-Virus.

If you’ve got another anti-virus program installed on your system, it will be detailed here.

In this example, Avast Antivirus is protecting the computer and NOT Windows Defender.

When a third-party anti-virus program, such as McAfee, Norton, Avast etc, is present on the system, Windows Defender is effectively turned off.

Avast is indicated as being the primary antivirus program.
Avast Antivirus is protecting the system.

Third Party Antivirus Programs.

If you do see another antivirus program listed here, then that’s what you’d use to run virus scans of your computer.

How To Scan Your Computer With Avast Free Antivirus 2024.

How To Scan PC With AVG Free Antivirus 2024.

If you don’t have any other anti-virus protection installed, then on the Virus and Protection page, you will see something like this.

No mention of any other programs.

To return to the Security at a Glance page, click the back arrow in the top left of the window.

Windows Defender is main antivirus protection. Also the back button is indicated.
Windows Defender is currently monitoring the system.

How To Scan Your Computer With Windows Defender.

Microsoft Windows Security works in the background monitoring your computer. But just like any other AV software, it can miss things.

Malware can slip through the net. As such, it’s worth getting into the habit of running a manual scan of your computer regularly.

To scan your computer, open Windows Security and then click VIRUS AND THREAT PROTECTION.

To start a Quick Scan, click the QUICK SCAN button.

How long a quick scan will take will vary depending on your PC, but normally no more than 5 minutes.

Quick scans only check the most likely areas of your computer where active malware might be.

Quick Scan button and the scan options link are marked in Windows Defender.
Click the Quick Scan button or Scan Options link.

Do You Think You May Be Infected?

If you think your machine may be infected, you can run a more thorough scan by clicking the SCAN OPTIONS link, which is just below the Quick Scan button.

Don’t wait for proof, sometimes it can just be a feeling that something is wrong. Intuition if you like, but whatever, run a full scan.

Windows Defender Scan Options.

Windows Defender has 4 scan options that you can use to find and remove malware from your computer. To start a scan, select your scan type and then click the SCAN NOW button.

  1. Quick Scan. Which we’ve just looked at.
  2. Full Scan. Scans everything on your computer. Every file and folder. This can take a long time.
  3. Custom Scan. With a custom scan, you can choose which folder is scanned, rather than scanning the whole computer. This one is useful for scanning USB drives and external hard drives.
  4. Microsoft Defender Offline Scan. Some malware can be impossible to either detect or remove whilst Windows is running. The offline scan will restart your computer and initiate a virus scan before Windows loads up.
Quick Scan button and the scan options link are marked in Windows Defender.
Select the type of scan you want to perform and then click the Scan Now button.

Ransomware Protection In Windows Security.

Ransomware is one of the biggest threats that you’ll run into when using the Internet. What ransomware does is encrypt all your files (documents, pictures, videos etc) making them unusable. Until that is, you pay the ransom.

The best protection from ransomware is obviously, to not allow it to get on your computer in the first place. Windows Defender will monitor all the websites that you visit and anything that you download in an attempt to keep any malware off your system.

But it isn’t perfect. No anti-virus solution is perfect, either paid for or free, they all have weaknesses.

In an attempt to protect your most valuable files, you can set Microsoft Windows Security to control access to certain folders on your computer. When a folder is being protected, Windows Security will try to intercept any attempt to alter the files inside it. Thus foiling the encryption process. That’s the theory anyway.

How To Set Up Ransomware Protection In Windows Security.

Open Windows Security and then click Virus & Threat Protection.

Scroll down to the page to the Ransomware Protection section.


Manage ransomware protection option is marked.
Click on Manage Ransomware Protection.

In the Controlled Folder Access section, toggle the switch to on by clicking on it. You might see a UAC pop-up asking for permission to continue. If you do, click the YES button.

Ransomware protection is turned off and a mouse pointer is hovering over the toggle switch.
Controlled folder access toggled off. Click the switch to turn it on.
Ransomware protection is turned on and a green tick appears next to it.
Controlled folder access toggled on.

Selecting Which Folders To Protect.

By default, with folder access turned on, Microsoft Windows Security will protect the following folders, Documents, Pictures, Videos, Music and Favourites.

You can add your own folders to that list.

To do that, in the Controlled Folder Access section, click PROTECTED FOLDERS.

Again, you might see a UAC popup, click the YES button if you do.

The protected folders link is indicated.
The Protected folders link.

On the Protected folders page, you’ll see a list of all the folders that are currently being monitored.

To include another folder, click the ADD A PROTECTED FOLDER button

Add a protected folder button is marked.
The protected folders page in Windows Security. To add another folder, click the “Add a protected folder” button.

Now you need to find the folder you’d like to be protected from a ransomware attack.

Navigate to the folder, select it by left-clicking it once and then click the SELECT FOLDER button.

We have already covered navigating your computer earlier in the At Home Computer Course, if you missed it click

A user folder has been selected and the Select Folder button is indicated.
Find your folder, select it by left clicking on it once and then click the Select Folder button.

You’ll see the folder you selected appear in the list of protected folders.

From now on, Windows Security will carefully monitor the files contained inside this folder.

The aim is to intercept any attempt to encrypt these files.

However, you can use the folder and the files inside it just as you normally would. Outwardly nothing has changed. the folder will work as if nothing different was happening.

Protected folders list in Windows Security. A new user folder has been added and a green tick appears next to it.
The selected folder is now protected from ransomware attacks.

How To Turn Off Ransomware Protection In Windows Security.

You might find that the ransomware protection built into Microsoft Windows Security either interferes with or downright prevents you from using your computer in the way in which you want to use it.

For instance, converting files inside protected folders could be seen as being malicious activity and therefore prevented. After all, that is what ransomware does. It converts standard files into encrypted files.

If you find that the ransomware protection is interfering with your normal use of your computer, you can simply turn it off.

To turn off ransomware protection, open Windows Security and then click Virus & Threat Protection.

Scroll down to the Ransomware Protection section and click MANAGE RANSOMWARE PROTECTION.

On the Ransomware Protection page, click the toggle switch to turn it off.

Controlled folder access has been turned off.
Turn ransomware protection off if it interferes with the normal use of your computer.


Microsoft’s Windows Security does a reasonable job of protecting your computer from viruses and other malware. It is by no means perfect, but then neither is any other antivirus solution.

Maybe it isn’t as good as some of the third-party paid-for alternatives, but I think that many people don’t really need that level of protection. And besides, you can still get infected regardless of how much your antivirus cost.

I’m not saying that you shouldn’t buy protection, but simply that you shouldn’t feel pressured into it. You already have an effective anti-virus program on your computer.

Also, with ransomware protection becoming increasingly common in anti virus software, it’s good to see Windows Security keeping up. Give it a try, you might find that it saves your most important files.

At Home Computer Course.

How to update Windows.
Next Page

Stay Ahead Of The Game.

Windows needs constant updates to it safe and secure.

Keep Up With Home Computer Guides.

All the latest guides and articles published on At Home Computer delivered to your inbox.

No account needed, just add your email address.

Scroll to Top