Which license will I have?

I recently found out that I can still upgrade the Windows 7 that came with my laptop to Windows 10 using the MCT, but before I knew about that, I had already bought a Windows 10 license from not-Microsoft and had the machine activated with that. It's time for a refresh of the OS, and I was thinking about putting Window 7 back on it using the original OEM Windows 7 license stuck to the machine, then upgrading that to Windows 10 using MCT, so that I can have a Windows 10 license direct from Microsoft rather than the one bought from from elsewhere.

My question is this: If, in the future (after I have done the upgrade), I decide to do a completely fresh Windows 10 install, which Windows 10 license will the machine pick up? The one bought from not-Microsoft, or the one upgraded from the OEM Windows 7 license?

Activation works a little differently in Windows 10. Whether you used a key to activate W10, or upgrade from an activated W8/8.1/10 to W10 the result is the same. You get a digital license stored on the Microsoft activation servers for the edition you obtained (Home or Pro) and linked to the unique hardware ID of your PC. The key you used is not recorded on the activation servers, only the hardware ID, the entitlement to run Windows 10 and which edition you are entitled to run.

Assuming your W7 licence is for the same edition you already have then reinstalling W7 then upgrading it will make no difference to your digital license. It would only be worth doing if you have W10 Home at present and your OEM W7 is Pro. As your profile says 'Windows 10 Pro' I'm guessing that is not the case.


You can do a clean install right now, skipping entering a key if asked, and it will activate from your existing digital license.

Hm.. I hadn't considered the edition. I believe the one I was using previously was Pro, but the one I would like to use going forward (since it is all through the OEM and Microsoft) is Home. Would that mean that, if reinstalling Windows 10 with fresh media, I should select Home (is there an option to do that?), and then it will use the license upgraded from OEM Win 7 Home?

A PC can have more than one digital license linked to it's hardware ID. You currently have a digital licence for Pro. If you install W7 Home then upgrade to W10 you will gain in addition to the existing Pro digital license a digital license for W10 Home.

Starting with Windows 8 an OEM PC was no longer supplied with a CoA sticker with an OEM key printed on it, instead the OEM key is embedded in the bios. On a clean install Windows 10 Setup will read this key from the bios and automatically install the edition that the key is for, Home or Pro.

For a clean install on a machine built for Windows 7 there is no key in the bios so Setup will ask you for a key. You can skip entering a key, in which case it will then ask you to choose which edition to install. If this PC has a digital license for Home and another for Pro you will be able to choose either and it will activate from the appropriate digital license as soon as it can contact the activation servers.