A couple of weeks ago my screen went blank then up comes one showing what looked like the My Computer screen, it showed flashing red triangles telling me that it was under a virus attack and to click something to stop it.
I didn’t do it, of course.
I X’ed the window and did a virus scan. It found nothing.
Same/similar thing happened to me. The bogus screen made it look as if it had come from Microsoft. And at first, the warning didn’t want to close. IIRC, I just rebooted and did a scan; nothing came of it, thank goodness.
I try to run scans every night (when I remember), I launch MalwareBytes one night, and McAfee the next. So far, so good.
My daughter, unfortunately, DID click...and the virus totaled the system.
In the end, I had to reformat and do a clean install. NOT good!