Is this counterfactual pop up on screen from Microsoft?

Dear community!

Since yesterday for the second time I get pop up messages on my screen

telling me I did not have the genuine Microsoft operating system,

which is not true: I bought it in 2007, I have the original licence nr. with bar code etc. here, only the installation (Jan 5th, 2008) was not made by me but a member of the IT department of our university. I had a lot of trouble after installation and even corresponded personally with Microsoft and Acer about how to correct it, I still have the letters that went back and forth.

The question they are asking me in the popup is completely beside the point : "do I want to replace the genuine Microsoft product now or later?"

It is so astute, like: "Did you stop to beat your wife, yes or no?" any answer, either way, will make you appear like a heel, and you don't have a chance to prove it is counterfactual.

What on earth can I do, where can I write to and present my papers containing the original key?

Or is this a fake or malware trying to intrude?

Have others experienced such popups?

I tried to make a screenshot which -for the first time- does not work.

Any input is much appreciated,

and thank you in advance,

best,

Katharina