If your PC runs Windows 7 or Windows 8.1, you may wind up with Windows 10, whether or not you want it. And if you don’t have it by now, you probably don’t want it for good reasons.

Last August, I upgraded my PC from Windows 7 to Windows 10, just to see what all the fuss was about. Here’s what I learned from that experience:

• It adds no functionality that’s of use to me — and I’m a heavy PC user (but not a gamer or developer).

• It took a lot of tweaking of my privacy settings to ensure that I wasn’t sharing information that I don’t want to share (e.g., passwords).

• Settings in general are harder to navigate than the settings in Windows 7, where Control Panel is configured much as it was in earlier versions of Windows.

• In some instances Windows 10 doesn’t believe that I’m the administrator of my own PC, and won’t allow me to move certain files directly from one location to another. There’s a work-around, but it’s time-consuming and inconvenient.

There’s more, but the bottom line is that I learned enough about Windows 10 that I chose not to install it on my wife’s PC. And I recommended to others that they not bother.

Then I learned that if a Windows 7 or Windows 8.1 PC is set up to download and install Windows updates automatically, it will become a Windows 10 PC — like it or not. Yes, there’s a way to reverse the “upgrade,” but why should anyone have to undo what they didn’t choose to do in the first place?

I’m sure that Microsoft’s arrogant action is legally justified by the fine print in the license that almost no one reads when they buy and install a computer. But it’s the kind of action that leads people to seek out alternatives. Alternatives are already at hand (e.g., Mac, Linux, Chrome), and more will surface when the blood of Windows is in the water.

You’d think that Microsoft would have learned a lesson from the precipitous decline in the use of Internet Explorer relative to other web browsers, the rise of alternatives to Microsoft Office, and stiffer competition in other software markets.

It may be a long time before Windows is no longer the dominant operating system for PCs, but its dominance will end if Microsoft doesn’t stop acting like it owns the market. It doesn’t.