But note that a key can only be used on one PC at a time, so if you use that key for a new PC build , any other PC running that key is out of luck. Downsides of Using an Old Key When using an older Windows key to activate Windows 10, you may run into complications if Microsoft isn't sure whether you're eligible to update or not. But that seems to be happening less in recent months and years. Don't Activate Windows: I have colleagues who have used non-activated versions of Windows for years without Microsoft ever shutting it down. Microsoft brands PCs running an unactivated version of Windows 10 with a watermark in the bottom-right corner of the screen. A Microsoft spokesperson told me that activating Windows 10 ensures you have a legitimate copy of Windows 10, and the watermark is an attempt to alert consumers that their version could be false.
Medium-to-high effort: Try a Windows 7 or 8 key Microsoft Price: When Microsoft first launched Windows 10 back in , it offered Windows 7 and Windows 8 users a truly free, no-strings upgrade to the new operating system. The promotion was only available for just one year—presumably to accelerate push up Windows 10 adoption rates—and expired in July But even though Microsoft officially ended this program three years ago, it still has yet completely shut everything down.
Windows 10 Home vs. Pro vs. S Mode Which version of Windows is the right option for you? By Tyler Lacoma October 30,
Buying a Windows 10 License through the Microsoft Store