How to remove malware and adware from a Windows PC (Windows 11 and 10)

Pop-up ads that appear out of nowhere, a search engine that changes by itself, unfamiliar toolbars and unexplained slowdowns usually do not come from a single file. They are the combined result of malware, adware and unnecessary programs running in the background.

On Windows 11 and Windows 10 you do not need to buy extra software for this job: Windows Security can run both a normal scan and an offline scan that works before Windows loads.

The order below moves from easy to harder: first update the protection definitions and scan, then clean up browser extensions, startup apps and installed programs.

1. Open Windows Security Search for "Windows Security" in the Start menu and open the app. You can reach the same place through Settings → Privacy & security → Windows Security. In the app, go to Virus & threat protection; under Current threats you can see when the last scan ran and whether any alert is waiting for you.
2. Get the protection updates Open the Protection updates section on the Virus & threat protection page and check for updates. A scan run with outdated definitions will miss newer infections. Then open Settings → Windows Update and install any pending Windows updates as well.
3. Keep cloud-delivered protection on In the Virus & threat protection settings section, open Manage settings. Confirm that Cloud-delivered protection and Automatic sample submission are both turned on. With these two settings enabled, files that have never been seen before are much more likely to be recognised.
4. Run a full scan Go to Virus & threat protection → Scan options, select Full scan and press Scan now. A full scan checks every file and program on the device, so it takes much longer than a quick scan and the computer runs slower while it works. Start it and leave the computer on; you can keep using it.
5. Run an offline scan When the full scan finishes, return to Scan options, select Microsoft Defender Antivirus (offline scan) and press Scan now. Save your open files first: this option restarts the device and runs the scan in the Windows Recovery Environment, before Windows loads. That is how infections which hide themselves while Windows is running get caught; when the scan is done the computer restarts on its own.
6. Read the protection history After the computer comes back up, open Windows Security and go to Protection history. The results of the offline scan appear here. Click each entry to see what was found and whether it was quarantined or removed; if an action is still pending, apply the recommended one.
7. Review your browser extensions Adware often survives as a browser extension, so the pop-ups continue even after a clean scan. In Chrome, select More → Extensions → Manage extensions at the top right and remove anything you do not recognise or do not remember installing. If you use another browser, open its own extensions page and do the same.
8. Reset browser settings to default If the home page and search engine still are not yours, reset the browser. In Chrome, open Settings from the menu at the top right, go to the Reset settings section and use "Restore settings to their original defaults". This does not delete your bookmarks or saved passwords; it only returns changed settings to their original state.
9. Trim the startup apps Open Start → Settings → Apps → Startup. Switch every app you do not recognise or do not need to Off. You can see the same list by right-clicking Start, opening Task Manager and going to the Startup apps tab, where you select a row and choose Disable.
10. Uninstall programs you did not install Open Start → Settings → Apps → Installed apps and sort the list by install date. If something appeared in the last few days that you did not install, select it and click Uninstall. When you are done, run one more full scan; if the problem persists, free up disk space, update Windows and, as a last resort, reset the PC and restore your files from backup.

⚠ This guide is general information. Yudum cannot be held responsible for the outcome of following it; for official procedures always rely on the institution's own statement. Steps and fees change over time.

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