Alright. I do not understand how this works.
I have a PC and a mac. Both are running windows 7. The macbook runs Home (dual boot with OSX) and the desktop Pro.
I downloaded the windows 10 media creation tool as i want to have the ISO so i can make a fresh install. But this page:
http://windows.microsoft.com/en-us/windows-10/media-creation-tool-installstates that and i quote
"If you upgraded to Windows 10 on this PC by taking advantage of the free upgrade offer and successfully activated Windows 10 on this PC in the past, you won't have a Windows 10 product key, and you can skip the product key page by selecting the Skip button. Your PC will activate online automatically so long as the same edition of Windows 10 was successfully activated on this PC by using the free Windows 10 upgrade offer. "
SO my question is, i have to first do an upgrade then if i want a clean install i format my PC and dont use a key code? how will MS know its the legit upgrade? and If after i do the windows 10 upgrade with my windows 7 key (im assuming thats how it works) and i dont like 10 can i still use that key for 7?