The Redmond doctor came into the room, huffed a chair into place, but wouldn't meet Windows 7's eyes, just stared at the desk. "I'm afraid it's bad news," the physician said.

Windows 7 let out a long sigh.

"It's terminal," the M.D. said. As if Windows 7 hadn't known it was on borrowed time since July 2015. That scare in the fall of 2012 had been irksome, nothing more. But then three years later, the end was clearly in sight. And here it was.

"Ten weeks," the doctor said, gazing out the window at the fall leaves. "Maybe eleven. But then...."

What happens to Windows 7 then?

Nothing immediately.

The operating system will continue to work or not, as it did or didn't, for each user the day before support retirement. That's important to remember, if only because some still don't — assuming that after midnight on Jan. 14, 2020, the OS screeches to a stop.

Even Microsoft reminds customers that Windows 7 will continue to run post-retirement, although it could move those reminders closer to the top of its to-do list. In this FAQ about the end of support, Microsoft waited until the fifth item before making note of the operating system's resilience. "If you continue to use Windows 7 after support has ended, your PC will still work," Microsoft pledged, also noting, "Your PC will continue to start and run."

Good to know, thanks.

But customer support comes to a halt — theoretically, Microsoft's phone- and chat-based support won't answer questions — as do security updates. Yet unless Microsoft issues an emergency update in the four weeks after Jan. 14, the first fixes Windows 7 users will miss arrive Feb. 11. Until then, an out-of-date Windows 7 system will be as patched as if support had continued.

What happens to Office when Windows 7 drops from support?

That depends on the type of Office. Office 365, the version paid by subscription — whether for one, as in Office 365 Personal, or for thousands, as in Office 365 Enterprise E5 — will continue to receive security updates on unsupported copies of Windows 7 until January 2023.

That's the good news. The bad? Office 365, whose premise is one of constant evolution, will not upgrade to new features or functionality. The feature set, in other words, will lock down and stay that way.

On the Office flip side — those versions sold as "perpetual licenses," such as Office 2010 or 2016 — will be supported through each suite's standard span. (Remember: Perpetually licensed Office, a.k.a. non-subscription Office, only receives bug fixes, never feature updates or improvements.) Office 2010, for instance, will be supported until Oct. 13, 2020; Office 2013, until April 10, 2023; and Office 2016, until Oct. 14, 2025.

The most recent perpetually licensed suite, Office 2019, is supported only on Windows 10.

Microsoft did set a caveat, however, on Office support. "If the problem is a result of the combination of Office and an unsupported operating system, the problem will not be supported (emphasis added)," the company stated.

The January 2023 end-of-security-updates deadline wasn't plucked from the air. It was chosen because that's how long Microsoft will provide Windows 7 patches for payment through its Extended Security Updates (ESU). Microsoft realized that if it sold ESU to commercial customers, it also had to keep patching Office.

What about Internet Explorer?

Unlike Office, Microsoft will stop patching Internet Explorer 11 (IE11) at the same time it halts updates to Windows 7. In other words, on Jan. 14, 2020.

"As a component of Windows, Internet Explorer follows the support lifecycle of the Windows operating system it's installed on," Microsoft says — and has for ages, since that's been boilerplate for seemingly forever. But elsewhere, the firm put it plainly. "Support for Internet Explorer on a Windows 7 device will also be discontinued on January 14, 2020," it said here.

The only way to keep receiving IE11 security updates in Windows 7 is to pay for Extended Security Updates (ESU).

What happens to the antivirus defense we use?

That depends on the antivirus vendor's policies and practices.

Just as happened at the retirement of Windows XP in April 2014, expect that most credible AV makers will continue to pump out new definition updates — the "fingerprints" that identify newly-found malware to the scanner — for Windows 7 long after the OS has fallen off the support list. The three-year availability of Extended Security Updates (ESU) to business customers will guarantee AV vendors that cater to the corporate market will keep definition releases going.

AV support may quickly be limited to issuing definition updates, although some vendors will continue to refresh products with new or enhanced features.

For reference, Symantec moved Windows XP (retired 4/14) and Vista (4/17) to what it calls "Maintenance Mode" only in June 2018. As of that date, Symantec said, "New product capabilities will no longer be provided." But already-installed software "will continue to receive the latest malware definitions" as well as "vulnerability updates and compatibility fixes."

Microsoft has not yet said what it will do for Security Essentials, the free anti-malware product for Windows 7. Again, a look to Windows XP is worthwhile: Microsoft provided definition updates for more than a year after XP's retirement.

What happens if we can't get off Windows 7, but can't run unpatched PCs?

Microsoft will gladly sell commercial customers, from the smallest businesses to the largest enterprises, what it calls "Extended Security Updates," or ESUs, that provide security updates to patch "Critical" and "Important" vulnerabilities through mid-January 2023...for a price.

The per-device plans will be sold in one-year increments for up to three years, with prices for larger customers running as high as $350 per PC for all three years. (Costs for smaller businesses won't be revealed until Dec. 1.)

Although Microsoft dubbed ESU the "last resort" for Windows 7 customers, it spent a large chunk of this "End of Support FAQ" describing the service, drawing its boundaries and extolling its benefits. ESU is, by far and away, the most transparent post-retirement security support concept Microsoft has launched. The company recognizes that many businesses will not make the deadline and so it wants a solution, temporary if that, or is eager to use what may be the last ever such OS transition to generate additional revenue.

Or both.

Note that ESU has no bearing on security updates for Office 365 ProPlus — the part of an Office 365 subscription that provides the locally installed applications — on Windows 7. Even Windows 7-powered PCs that are not covered by ESU will continue to receive patches for Office 365 ProPlus. Microsoft made that clear in the FAQ: "Windows 7 ESU will have no impact on support for Office 365 ProPlus on Windows 7," it read.