Here’s a sentence you never thought you’d read: Microsoft Corp. doesn’t want your money.

Well, not for the latest version of its Windows operating system, anyway. But Microsoft does want to preserve its dominance of the personal computer. And even though the famously ruthless Bill Gates no longer rules the empire, his company still knows how to deal from the bottom of the deck.

Consider Microsoft’s efforts on behalf of its Windows 10operating system, which it is giving away at no charge to consumers whose personal computers run older versions of Windows. Just download and install between now and July 29. After that, you’ll have to pay $119 or more.

It sounds irresistible, and so far more than 300 million machines have been upgraded. But many people are happy with their current Windows setup. Microsoft isn’t. The company wants us all standardized on Windows 10. Hence it’s carried out a series of sneaky tricks meant to force the new software onto all our PCs, whether we want it or not.

It began last year, when Microsoft started downloading Windows 10 — all three gigabytes of it — onto people’s hard drives without asking permission. Then the company tried making the upgrade a “default’’ setting in its Windows Update service, which usually just installs bug fixes and security enhancements. Microsoft apologized for that one, but some people switched off Windows Update altogether, sparing them the upgrade but making their computers less secure.

Then sometime this spring, Microsoft came up with the tackiest tactic yet. A big message box appeared on millions of computers, announcing they were “scheduled’’ for a Windows 10 upgrade. Many who saw this box just clicked the “X’’ in its upper-right corner — the standard way of shutting down Windows programs. But in this case, clicking the “X’’ amounted to confirmation the user wanted an upgrade. Only if they read the small type in the message would they learn how to actually refuse the upgrade.

It’s a deceitful way to distribute an excellent product. I’ve used Windows 10 since its early preview versions rolled out in 2014. It’s stuffed with smart features like voice-activated search, faster access to your most frequently used files, the ability to create multiple desktops, each with different apps and a different look, and a fast new Web browser with tools to add personal notes to Web pages.

And Windows 10 is as user-friendly as Windows 7, mainly because it abandons the worst features of the appalling Windows 8. I’ve upgraded all four of the family’s PCs, and I’m glad I did.

So when a product is this good, and free as well, what’s with the scorched-earth tactics?

It’s all about keeping Microsoft at the center of the computing universe. With so much competition from Apple iPhones and iPads, Android devices, and cheap laptops running Google Inc.’s Chrome operating system, sales of Windows computers have plunged. Millions are learning that they can get along with a five-year-old PC, or maybe no PC at all.

So starting with Windows 8, Microsoft redesigned its operating systems to make it easier to program them with software tools such as HTML 5 and Javascript, which are popular with Internet developers. This is supposed to spawn a new wave of must-have PC software, capable of running equally well on PCs, tablets, and even smartphones — yes, Microsoft still makes phones.

But none of this hot new software will run on machines running Windows 7 or older — about 60 percent of the global PC market. So Microsoft must get its new operating system on as many machines as possible, as quickly as possible. Hence the company’s ambitious goal: 1 billion Windows 10 users by 2018.

No wonder they’re giving the stuff away. And if millions of users choose to reject Microsoft’s temporary generosity, the company must simply find new ways to motivate them.

Microsoft makes no apologies for its relentless campaign.

“The Windows 10 upgrade is a choice,’’ the company said in an e-mailed statement. “People receive multiple notifications to accept the upgrade, and can reschedule or cancel the upgrade if they wish. We’re continuing to listen to customer feedback and evolve the upgrade experience based on their feedback.’’

Well, here’s my feedback. It’s fun to see Microsoft showing a little swagger. Seems like old times. But remember that the company’s grandest era ended in 2001, after Microsoft’s tactics against rival Internet browers spawned an antitrust case that almost led to court-ordered annihilation.

This Windows 10 kerfuffle isn’t nearly as serious, of course. But bad habits have a way of getting worse. May I recommend an ethics upgrade? No charge, of course.

Hiawatha Bray can be reached at hiawatha.bray@globe.com. Follow him on Twitter @GlobeTechLab.