Hi, We have several machines that are running Windows 7. They are attached to machine tools and it will be very expensive to bring them up to Windows 10 so we purchased the extended support option for Windows 7 for these specific machines. I received a key but I am not sure how to apply it. I am assuming that I have to re-enter the product key and use the key that has been provided for the extended support but I want to be sure. I cannot afford to have any issues with these computers that require the extended support. I cannot find any specific instructions out there.