It's not as cut and dry as the moderator said. He is if you picked up a license for Windows 10 and installed it.
DEPENDS.... If you got a new laptop/PC, a lot of the corporate licenses are can be used to activate Windows 7, 8.1 or Windows 10. I personally have seen IBM, Dell and HP models like this. You need to select this the first install.
If your Windows 10 was upgraded from Windows 7, I have heard from people that if you install Windows 7 and use the original key, even 6-8 months later it will activate.