Media Center Product Key Error

I requested and received a product key for Windows 8 Media Center. I followed the installation instructions, but when I enter the product I get the message "This key won't work. Check it and try again, or try a different key. "

I've tried it several times over several days and get the same error. I've done a copy and paste and also typed it in. I also requested another key with a different email address and get the same results. My system runs Windows 8 (OEM) on a computer I built myself.

The build includes a Core i7-3770K, 16GB RAM and a touch screen.

 

Do you have to pay for the WMP License? Just curious. I'm seriously considering upgrading one of my laptops from W 7 Ultimate to W 8 Pro.

 

Thanks, that must be the problem. I didn't buy the special Pro upgrade offers because I didn't have an old OS to upgrade from. I guess I'll just have to fork out the cash for one now if I conclude I really need Pro on this system. I have another desktop and laptop with Pro that I can use. I didn't do a good job of reading descriptions for the various versions.

If I do an upgrade, do I have to do an install or can I just change the Win 8 Product Key. If so, how?

 

Thanks PeteC and Arie.