I'm going to post this a second time for those still wondering about Activation after fresh install and other FAQ.
I've contacted OP to have it added to the first page.
Things you should know:
• A Windows 7 or Windows 8/8.1 product key cannot activate Windows 10. Windows 10 uses its own unique product key.
• By default, Windows 10 builds are pre-keyed, meaning, you do not have to enter a product key and should not be prompted to enter one as long as you upgraded from...