If you see something similar to this:
This is a pretty common occurrence and nothing to be worried about. This is just a pop-up and your computer is not infected. The message is a scam that is trying to scare you into calling the displayed phone number so the scammers can get access to your computer and try to sell you some software you don’t need.
The pop up can be difficult to close. You can just restart your computer or close your web browser through Task Manager.
To close this through Task Manager, right-click the time in the bottom right of your screen, then click Task Manager.
Find your web browser on the list and right-click it then click End Task.
Sometimes when you reopen your browser the pop-up will display again if your browser is set to go back to the page it was last on when the browser closed. If this is the case, just close the web browser again through Task Manager. Now hit the Windows key + R on your keyboard.
This should bring up a Run window. Type www.google.com in the space provided then click OK.
This should open your browser on this website instead of going back to the previous one that displayed the pop-up.