Thank you. No, my only reason for the question is to know how to advise anyone who has actually used a Windows 7 or 8 Product Key to activate a Windows 10 clean install. I read about so many going through the steps of reinstalling and activating Windows
7 or 8.1 and then re-upgrading, in an attempt to get Windows 10 activated. But this has always seemed unnecessary to me. My Windows 7 and 8.1 upgrades were all done prior to November, 2015, when that method became available, so no Product Key was ever entered
and they all show the generic Product Key, if I use a utility to read it.
New Retail Windows 10 installs, of course, actually use a Product Key to activate Windows 10. I assume that new OEM installs have an embedded Product Key in firmware, like Windows 8.1 had. It can probably be read with the command:
wmic path softwarelicensingservice get OA3xOriginalProductKey
I believe that there is always a matching Edition Product Key. For most upgrades, it is a generic one from the list. In fact, there is a slmgr.vbs command specifically designed to clear the Product Key from the Registry "to prevent disclosure attacks":
slmgr.vbs /cpky. If you remove the Product Key with slmgr.vbs /upk - you will lose Windows 10 Activation. But losing Activation does not mean the device itself is not still Digitally Licensed. The current Windows install is
simply no longer activated.
Usage: slmgr.vbs [MachineName [User Password]] [<Option>]
MachineName: Name of remote machine (default is local machine)
User: Account with required privilege on remote machine
Password: password for the previous account
Global Options:
/ipk <Product Key>
Install product key (replaces existing key)
/ato [Activation ID]
Activate Windows
/dli [Activation ID | All]
Display license information (default: current license)
/dlv [Activation ID | All]
Display detailed license information (default: current license)
/xpr [Activation ID]
Expiration date for current license state
Advanced Options:
/cpky
Clear product key from the registry (prevents disclosure attacks)
/ilc <License file>
Install license
/rilc
Re-install system license files
/rearm
Reset the licensing status of the machine
/rearm-app <Application ID>
Reset the licensing status of the given app
/rearm-sku <Activation ID>
Reset the licensing status of the given sku
/upk [Activation ID]
Uninstall product key
/dti [Activation ID]
Display Installation ID for offline activation
/atp <Confirmation ID> [Activation ID]
Activate product with user-provided Confirmation ID