... and depending on my mood I have several strategies;
1. Just tell them you only have Linux, they'll hang up immediately.
2. Musical hold, put the phone next to a speaker and go on with your life.
3. Tell them you have several computers running various Windows versions, which one did you mean... do you have a hostname or IP address so I can narrow it down? You don't? So how do you know it was my machine again? Really? ... So can I speak to your manager. (So far I've never got a manager.)
4. Pretend to follow along with their instructions, honestly the most time consuming and least satisfying.
But the problem is not with us, it's with Joe User who for some reason is unaware that Microsoft isn't phoning everybody. Never underestimate the power of human stupidity.