The question that decides everything : do these adverts appear only in the browser, or also when it is closed ?
In the first case it is an extension or a browser setting, and cleaning up is simple. In the second, a program is installed on the machine and has to be tracked down. The treatment is not the same.
Where does it come from ? Almost always from installing free software whose pre-ticked boxes were accepted without being read, or from a fake download button on a file-sharing site.
This is where most parasites live. In every browser installed - there are often several, and all of them need checking - go through the list of extensions and remove anything you did not install deliberately. Be wary of any that promise discount coupons, video downloads or faster browsing.
Then check the home page, the default search engine, and the notification permissions, which often list unknown sites to revoke.
In Settings > Apps > Installed apps, sort by install date. Unwanted software usually arrives in a group on the same day, with names suggesting optimization, cleaning, weather, codecs or file conversion. Uninstall whatever you do not recognise.
A quiet trick, and one that often gets missed : the browser shortcut is edited to add an address at launch. The result is that the unwanted page comes back every time you open it, even after a thorough cleanup.
Right-click the shortcut, Properties: the Target field must end with the program name and its extension, with nothing after it. Delete anything that follows.
Some adware creates a scheduled task that reinstalls it after removal. If the adverts come back a few days later when everything looked clean, that is almost always the explanation. This check takes a little method, and it is typically the point where having someone do it saves time.
Do not install a cleanup utility found at random through a search : that is the main way this kind of program arrives, and the cure then becomes the disease. Be especially wary of tools offered by a pop-up window or by the advert itself.
If windows appear while the browser is closed, a program is running in the background. An offline scan from Windows Security often finds it - see removing a virus on Windows 11. If the symptoms return after a cleanup, a clean reinstall is the surest route.
This kind of cleanup is easily handled remotely, with no visit.
It is less destructive than a virus, but it watches your browsing, sells it on, and often serves as a way in for more harmful programs. There is no reason to leave it there.
Only if the problem is confined to the browser. If a program is installed on the machine, it will reconfigure the browser the next time you open it.
It hides the symptoms without removing the cause, and has no effect on windows appearing outside the browser. It is still useful as prevention, once the cleanup is done.
Would you rather we took care of it ? See our virus removal and cleanup service, in Lyon and across the Rhone.
A full cleanup, scheduled tasks included - they are what brings it all back.
Automatic assistant: it can make mistakes. Never share a password or a card number.
