Replacing Windows 10

So I got a used laptop (Dell Latitude 16GB RAM, 255GB SSD) and it came with Windows 10. I activated Windows with the product key that came with my laptop.

I immediately replaced Windows with Linux Mint Cinnamon x64. I'm happy with it, but I am now realizing I really need Windows to play any of the games I did before. So I now want to dual boot Windows 10. My question involves what happens once I make my bootable disc/drive.

Will I be able to use the same product key I activated Windows with originally to activate it for the dual boot install, or will I have to purchase a new one or something? If so I can reuse the key, is the process the same as installing any other new OS?

If you had Windows 10 activated previously on the laptop you need not re-enter they key. When prompted during installation click on "I don't have a product key" and it will automatically activate after installation is complete and you connect to the internet.

If you saved the key (by using a keyfinder to retrieve it) before installing Mint you could re-enter it but there is no need.

In either case if prompted you must install the same version (Home or Pro) that you had before. If you have your OEM key embedded in your firmware you'll not be asked.