Re: Allow the upgrade
I also did a revert to Win 7 after "spamgrading" to Win 10 on one of my laptops. It reverted without too much fuss but screwed up some parts of the schedule system in the process. Thankfully I made a backup before that happened so one full recovery later and all was well. Thankfully Microsoft knew how to write useful software back in those days!
spamgrading (v.) - To force users to change an application or system by forcefully pushing the change via the internet, usually requiring users to implement unusual measures to resist the change where it is unwanted, unneeded or has been shown to be unfit for purpose. See Windows 10