Hi ipso,
Here is a method of removing nagging Windows 10 upgrade popup and preventing automatic upgrade,
providing that you check and remove GWX.exe after each update in you current version.
I’m sticking with Win 7, too much risk that some software may not run on Win 10, plus all the privacy issues.
One has to be wary of free gifts (free win 10 upgrade – why ?)
Here is the link to that process.
http://www.dedoimedo.com/computers/windows-7-to-10-gwx-how-to-remove.html
Cheers
GT