You will need an internet connection and must be signed in as an administrator to change the product key and activate Windows 10.Device activation improvements: Microsoft has received a lot of feedback from Insiders on making it easier to activate Windows 10 on devices that take advantage of the free upgrade offer to genuine Windows by using existing Windows 7, Windows 8 or Windows 8.1 product keys.
Note: Please understand that the loophole that allows this to work could (and should, I think) close at any time: All Microsoft has to do is to is turn it off from the cloud, it wouldn’t even require an update to Windows 10.But leaving some wiggle room for an edge case like this is the right thing to do. As is always the case with Microsoft, however, a little communication would be nice.Changing the product key that you used to install Windows with might be necessary if you find out that your current product key is...When you upgrade to Windows 10 from an older Windows version (one that lets you upgrade for free), you rely on the operating system’s old (and authentic) product key to carry you through the upgrade.After that upgrade, that key is not upgraded itself so that it will work on Windows 10 clean installs.After upgrading your Windows 7 or Windows 8 installation to Windows 10, you might be wondering what product key you will use in case you want to do a clean install of Windows 10.We’ve already tried using the Windows 7 (or 8 if that’s your case) key during a fresh install, and it didn’t work.Note: The steps involved in changing your product key differ considerably depending on which Windows operating system you're using. It's important to take great care in making only the changes described below!Important: I highly recommend that you back up the registry keys you're changing in these steps as an extra precaution.You may recall that Microsoft has allowed customers to use to use valid Windows 7, Windows 8, and Windows 8.1 product keys to activate Windows 10 since last October.It did so primarily for people with Windows 7/8.x-based PCs, so that they could successfully activate on upgrades, or on later clean installs after an upgrade. last week, I expected this capability to end with the release of the Anniversary Update. Or after Windows 1607 was installed and fully updated. I used previously unused product keys to test this.