Pop-ups you did not ask for, a browser homepage that changed by itself, a fan that runs all the time, or friends getting strange messages from your accounts. These are the moments you start wondering whether your PC has picked up something nasty.
You do not need to buy an expensive antivirus to deal with it. Windows 11 comes with solid protection built in, and this guide shows how to use it to remove a virus from Windows 11 step by step, plus how to clean up afterwards so it does not come back.
Signs your PC might be infected
- Sudden pop-ups or ads, even when your browser is closed.
- A new toolbar, extension or search engine you did not install.
- The PC is much slower than usual, with high CPU or disk use for no clear reason.
- Antivirus or Windows Security has been turned off and will not turn back on.
- Unknown programs in your app list or Startup apps.
None of these prove an infection on their own, but two or three together are worth a proper check.
Step 1: Disconnect from the internet
If you strongly suspect malware, turn off Wi-Fi or unplug the network cable first. This stops it from sending your data out or downloading more junk while you work. You can reconnect briefly to update virus definitions in the next step.
Step 2: Update Windows Security
Open Start, type Windows Security, and open it. Go to Virus & threat protection and, under Virus & threat protection updates, click Protection updates > Check for updates. Fresh definitions make sure it recognizes the latest threats.
Step 3: Run a full scan
The quick scan only checks common locations. For a suspected infection, you want everything checked.
- In Virus & threat protection, click Scan options.
- Select Full scan.
- Click Scan now.
A full scan can take an hour or more, depending on how much is on your drive. You can keep using the PC, but it will be slower. When it finishes, review anything found and choose Remove or Quarantine.
Step 4: Run a Microsoft Defender Offline scan
Some malware hides while Windows is running. The offline scan restarts your PC and scans before Windows fully loads, which catches things a normal scan cannot.
- Save your work and close all apps.
- Go to Virus & threat protection > Scan options.
- Select Microsoft Defender Antivirus (offline scan) and click Scan now.
The PC restarts and the scan runs for about 15 minutes. Afterwards, check Protection history in Windows Security to see what was found.
Step 5: Remove suspicious programs and extensions
Antivirus does not always flag adware or “potentially unwanted” programs.
- Go to Settings > Apps > Installed apps, sort by Install date, and uninstall anything you do not recognize that appeared around the time the problems started. If you are unsure, search the name online first.
- In your browser, open the extensions page and remove anything you did not add yourself.
- Reset your browser settings if your homepage or search engine keeps changing. In Chrome, it is Settings > Reset settings > Restore settings to their original defaults.
Step 6: Check startup apps
Malware likes to launch with Windows. Open Task Manager (Ctrl + Shift + Esc), go to Startup apps, and disable anything unfamiliar. Right-click and choose Open file location if you want to see where it lives.
Step 7: Get a second opinion
No single scanner catches everything. A free on-demand scanner such as the free version of Malwarebytes can run alongside Windows Security without conflict. Download it only from the official website, run a scan, then uninstall it afterwards if you like.
Step 8: Change your passwords
If the PC was infected, assume any password typed on it may have been captured. From a clean device, change the passwords for email, banking and social media first. Use the guide on creating strong passwords and turn on two-factor authentication so a stolen password alone is not enough.
When nothing works
If the infection keeps coming back, the cleanest fix is to reset Windows. Our guide on how to reset Windows 11 without losing your files walks you through it. Choose Remove everything if you have your files backed up and want to be completely sure.
How to avoid getting infected again
- Keep Windows and your apps updated.
- Download software only from official sites or the Microsoft Store.
- Be wary of email attachments and links, even from people you know. Our guide on how to spot a phishing email helps here.
- Leave Windows Security turned on. Microsoft has more guidance on its Windows support site.
Quick recap
To remove a virus from Windows 11, disconnect from the internet, update Windows Security, run a full scan and then an offline scan. Uninstall unknown apps and browser extensions, clean up startup items, and get a second opinion from a reputable free scanner. Finish by changing your passwords from a clean device.
