Thank you, DeaconFrost and GamerwGlasses for your useful responses!

Does anyone know how I can "unreserve" Windows 10?
I once reserved it, Microsoft downloaded the file and I decided no to install it right away.
After all, Windows 7 is good for another five years...

No one has even a suggested answer?

A brief apology: I'm probably too old to mess with this stuff (pulling 80,) but I like to try. Please be patient with me, and ask for details if I am not stating my problem clearly. I have...