Yeah, the exact definition of "major" hardware change is kept as a secret by Microsoft so that it's not easy to defeat that activation mechanism for pirates. T

Yeah, the exact definition of "major" hardware change is kept as a secret by Microsoft so that it's not easy to defeat that activation mechanism for pirates. The newer version (version 1511 and above) of Windows 10's digital licenses are essential a private key (as in asymmetric cryptography, called digital entitlement[1], stored in UEFI), as opposed to the a 25-character product key we used before. If for whatever reason the activation program cannot find that key, it won't be activated. [1]: https://support.microsoft.com/en-us/help/12440/windows-10-activation https://support.microsoft.com/en-us/help/12440/windows-10-ac... > which in my case was from almost 10 years prior. Luckily enough, I had it archived. If you bought your Windows license online with a Gmail address, Google has you covered. https://myaccount.google.com/purchases https://myaccount.google.com/purchases