The easiest way of getting the Windows OEM install key is to use a FREE program called “OEM Key”
The website you can find it as is located here: https://neosmart.net/OemKey/
I have downloaded it and saved a copy of the OemKey software and put it on my Web Server.
Links you might like to read:
How to install Windows Professional on a machine that has a BIOS Key that is for the basic version of the OS.