If you don't upgrade to Windows 10 by tomorrow, you'll have to pay $119 to get it
Starting July 30, you'll need to pay $119 for the Windows 10 Home edition, or get it free on a new PC, marking the end of Microsoft's year-long complimentary upgrade promotion.
Here are Microsoft's instructions for upgrading, or you can use the "Get Windows 10" app that's likely already sitting in your machine's taskbar.
If you've been on the fence, take heart: Windows 10 is already pretty great, and on August 2nd, it's getting the Anniversary Update - a big, free pack of features that also make a lot of desirable little interface tweaks.
And if you're determined to stay on Windows 7 or 8, come hell or high water, there's good news for you, too: Once Windows 10 stops being free, Microsoft is promising to stop sending those incessant and annoying reminders to upgrade.
Personally, I've been using Windows 10 for the last year. And while I can't speak for its value for somebody coming from previous versions of Windows, it was good enough to get me to switch from using Apple's Macbooks. So maybe give Windows 10 a shot. You might be glad you did.