If you are reading this article, I think you already know that yes, it is possible to install and activate Windows 10 on your computer using an existing Windows 7,8 or 8.1 product key. And that even after the July 2016 GWX free upgrade offer. Your Windows 7,8,8.1 product key will be converted to a reusable "digital license". Reusable means that we can reinstall Windows 10 whenever we want (on the same computer, same or almost the same hardware) without the need to use a product key again for the activation process.
So, what's the catch, why isn't legal to do that while Microsoft servers does activate Windows when installed using an official disk and a legally obtained Windows 7,8 or 8.1 product key?
I decided to ask the Microsoft Support for that, using their Twitter account @MicrosoftHelps
Read and draw your own conclusions (or ask a lawyer).
Q:: Hi, can you confirm that installing and activating Windows 10 using an existing Windows 7,8,8.1 OEM/GGK/Retail key is legitimate? We have some laptops in our company that have missed the "free to upgrade" offer, do we need to buy W10 GGKs or Retail keys for that?
A:: Let's take a look and find a solution! We found a discussion from our Community Forum which could be a useful reference for you. Check the answer of Andre Da Costa posted on this article: http://msft.social/YWj2FO . This will guide you on how to install and activate Windows 10 using your Windows 7 or Windows 8 product key. Let us know the results should you need further assistance. -Sher
Q:: Hi, my question was not how or if it can be done, but instead if it is legally to do that on 2019 without violating the law or other Microsoft licensing rules. To be clear, I have one windows 8.1 laptop and I want it legally upgraded, so, is this upgrade (by fresh installing Windows 10 using Windows 8 existing key) legit as of 2019?
A:: No it's not. Not unless you had that same device already upgraded to the former free Windows 10 upgrade which was offered 2016. _Drin
Q:: Hi, thank you, so while MS Servers will allow W10 installation using a W7,8,8.1 genuine key (and thus activating W10 with a digital licence), doing that for the first time after the July 2016 GWX period will lead W10 to an unauthorized install according to .... (please specify). My goal is to clearly inform small business and home business owners to stay away on doing this kind of technically allowed upgrade and rather stay with current OS or buy a separate Windows 10 license for theyr existing devices.
Q:: Hi, is there any authorized person able to answer me such a simple question? A simple NO without no cover (EULA?) it's not enough from a legal perspective, not while all over the microsoft support sites the moderators says yes and further instruct on how to do it. Again, I just fresh installed Windows 10 on a laptop and entered my Windows 8 COA key to activate it. Can Microsoft sue me for doing that? [...]
A:: You can only activate Windows 10 using a Windows 7 or Windows 8.1 product key, if you've already used it to activate your Windows 10. Hope this helps. -Jiro
Q:: AFAIK the only agreement between me as a consumer and Microsoft is EULA, please let me know where EULA (for Windows 10) specifies that I can't install, activate and use Windows 10 on a computer previously used with a valid Windows 7,8,8.1 key. Maybe something regarding GWX free upgrade end time, anything. Evasive answers are not an option.
A:: Please check this link http://msft.social/Qe20Oz for MICROSOFT SOFTWARE LICENSE TERMS. It doesn't specify that you can't install Windows 10 on a previously used computer that has a valid Windows 7, 8, 8.1 key. However, on your situation since you've missed the free upgrade to Windows 10 that ended last July 29, 2016 http://msft.social/NsEh8g , you will need to buy Windows 10 product keys to upgrade. For more inquiries about upgrading to Windows 10, we suggest that you reach our Support team here: http://msft.social/YUcZyO . Keep us posted.Finally, if you are running a small/home business, you may find that using Ubuntu OS (or Pop!_OS) may be enough to satisfy your IT requirements, being email, document processing, web applications and internet browsing, document printing, local and network security.