There’s a scam going that involves the popping up of an official looking notification window that says basically “AV360 virus identified” or “AV360 virus detected” or some such, and gives you the seeming choices of “yes”, downloading the fix, “no”, not downloading the fix, or “”, closing the pop-up.
DO NOT CLICK ANY OF THOSE!
If you do, you activate the virus, and then, after getting more and more crap about it, finally subscribe to a paid fake anti-virus service that does absolutely nothing except “remove” the “AV360” “virus” that it just planted. It’s just a scam to part you from your money.
INSTEAD, hit Control/Alt/Delete, which will bring up your Task Manager, and you can then close that little bugger without falling into their clutches.
DO NOT CLICK any buttons, anywhere that offer to update your anti-virus or to scan your computer for viruses. Get and maintain a reliable anti-virus software agent (I use AVG, which the above scam seems to be pretending to be) and keep it updated through that system.