The other method is to uninstall and hide update KB3035583. That will stop it from trying to install Windows 10 upgrade. You can then clean up the install files if they were preloaded.
Did that to my old Windows XP laptop that I upgraded to Windows 7 and works fine. No longer trying to do the Windows 10 update. Every other machine is running Windows 10.
I am running Windows 7 here, and did uninstall and hide the KB3035583 update on 3 computers. This worked fine for about 3 weeks or so. Then, when a Windows Update notification came, lo and behold, KB3035583 was on the list of needed updates, even though I had hidden it. MS is being a bit sneaky, so this "uninstall and hide" approach becomes a game of "whack a mole" because something in Windows Update unhides it without your consent. So I manually did a registry edit as recommended by Microsoft and as described in
my earlier post. I did this back in February and it's worked fine ever since. The
Never 10 and
GWX Control Panel applications do this step behind the scenes too, plus a couple of other things. So I thought I'd pass on the article for those who, rightly, don't want to mess with the registry manually using the Registry Editor.