Suddenly, you have pop-ups in the corner. The sort of spam advertisements that you know never to click on, interspersed with suggestions that your anti-virus is out of date.
And you didn’t download anything. What happened?
One possibility is that among those many “allow notification” requests that you turned down, something malicious got through.
Strictly speaking, there is no reason that request had to include the “no” option, or that the “no” button you clicked was actually that.
If it’s in the notifications, go through the settings on your internet browser and see which websites are allowed to send you notifications. Remove permissions for anything you don’t recognize.
Trego's Mountain Ear 