screams at you & tells you not to shutdown your computer etc ??
My 95 year old Mom (who spends way too much time on facebook) came up with this problem a few days ago. I reverted her Windows 11 computer to a previous date & everything worked fine.
(If I got a message that said to not turn the computer off, I'd think for a moment trying to figure if I'd actually been infected with something, & then I'd be apt to do just that - turn it off.)
-------------------------------------- BANK OF AMERICA.COM ONLINE BANKING SUCKS IN THE HUGEST WAY IMAGINABLE
Newegg.com's new image gallery layout sucks in the hugest way imaginable too ! And now they're using JavaScript to "turn" pages to boot ! SUCKS
It's not a virus, it's a simple browser hijack. Start by turning off notifications from all browsers. Check the browser for suspicious add-ons or extensions. Install Malwarebytes Browser Guard in addition to the Ublock Origin that Rube mentioned.
Behind every good computer... is a jumble of wires 'n stuff.