I know that at one time it was possible to do this when you were doing a clean install (and, of course, doing this legally by only having used that Windows 7 product key for a single installation of either Windows 7 or Windows 10, but not both at once using the same key on two different machines).
I have actually never attempted this, and haven't seen it discussed recently. I know someone that's got a Windows 7 Pro key that's unused and they were thinking about installing Windows 10 instead. Can you supply a Windows 7 Pro key and have Windows 10 Pro activate, or must you install Windows 7 Pro and do an in-place upgrade (which does still work, at least as of 7 weeks ago when I did my latest one).
Edited by hamluis, 02 July 2019 - 01:09 PM.
Moved from W10 Spt to W10 Discussion - Hamluis.