I got locked in one of those update loops. You know what I mean, probably. My Windows 10 would start an automatic update, then fail, and then reset itself to a previous version. This would happen all of the time.
I managed to use one of the methods on this link to successfully do an update:
https://www.alphr.com/microsoft/1001411/how-to-fix-windows-update-in-windows-10-if-it-becomes-stuck-1
Now, here is the reason why I am making this post. In case I want to ever do a completely fresh reinstall of Windows 10, I want to know how to do this because the CD (DVD, maybe?) and all I have is the ("OEM"?) sticker with the associated ID numbers.