How to change the key in pirated Windows?

Question

Windows

Good afternoon.
I have a pirated Windows 7 on my computer. I found out that at work you can get keys for free through the MSDN system, which you can also use for personal purposes.
I received such a key, but in the menu where it is usually changed, I simply do not see such a button. Perhaps something has been hacked so well before. Is there a way to somehow change the key to a licensed one?
Do I understand correctly that if I use it, then my version of the OS will become legal?

Answer 1

The solution turned out to be simple.
I ran Windows Anytime Upgrade and entered the key I got from MSDN. After that, a reboot occurred, and everything was fine, the OS was activated.

Answer 2

slmgr.vbs there is such a script in each system
install the key
slmgr.vbs /ipk the key the
version will become legal, but in the case of a biased check, you will not prove this (there is no sticker, there is no document certifying the purchase)