I got a phone call today from Alex. In a barely understandable accent he told me that he saw that my computer was full of harmful files and wanted to help me. When I expressed distress at the problem, he turned me over to the WindowsCare (a partner of Microsoft!) supervisor. Paul had an equally strong accent. He wanted me to push the "windows" key and the "delete" keys (well I think that is what he said; hard to be sure).
That seemed like a bad idea, so I hung up.

I presume the goal was to turn something off, so I would have to pay them to learn how to turn it back on. So what do these keys do? Google doesn't show anything, but perhaps I misunderstood Paul.