About six months ago I had a window pop up on my computer screen.
It stated I had an infection and must contact them to get it fixed.
I don’t remember exactly what I did at the time, but it wound up with me either closing the window or simply turning my computer off.
I rebooted in safe mode. It booted up. I shut down again, and started he machine like normal.
It booted up and I didn’t see any residual effects.
Don’t know if I just got lucky or what, but it seemed to work.
Months later I haven’t seen any evidence of a problem.
Your case sounds like run-of-the-mill malware that hasn’t really done anything to your computer at that stage. It just comes up as a pop-up and pretends to have found various scary-sounding viruses. They are hoping you will contact them, whereupon they will talk you into downloading and installing their “antivirus” software, which will then steal personal information, credit card numbers, passwords, etc. (if these are saved somewhere on your computer). They’ll also charge you for the “privilege” of being robbed while they’re at it.