The computer is a Dell laptop that has Windows 7 Pro OEM pre-installed and pre-activated, and it has a Windows 7 Pro COA sticker. I want to upgrade to Windows 10. After that, I want to be able to clean-install Windows 10. After I upgrade to Windows 10, how do I clean-install Windows 10 ? Is it possible to back-up the activation before clean-install, and then restore the activation after clean-install ? I don't want to backup the entire C partition, because it requires alot of GB on the external hdd.