I've searched to the hill on this one but, don't know for sure... Example: I want to get Windows 10 for my 7 machine, JUST in case. So I have 7 installed. I back up my system, Upgrade to 10, and restore my system back to 7. A year down the line, I decide that I want to go to 10, will this license still be valid for Windows 10 as I did the upgrade on it before ? Or will 7 stop working because I did the upgrade ? I have about 8-10 licenses between Windows 7 and 8/8.1, I am wondering if I should install them on VM's do the 10 upgrade and roll back, so if I dedcide to do a 10 upgrade they would be able to do it at no cost later. Does anyone know this one for sure or was it said anywhere that this WILL work ? Thanks !