Need to purchase a key for Windows 8 Pro full version.

Hello there. I have a copy of Windows 8 Professional installed that is the full version that I downloaded and I want to make it legitimate by purchasing a key for it to activate my copy. Is this possible? I looked online and you can only buy the upgrade and I do not have a previous version of Windows to do an upgrade with. I just want to buy a key and make my copy legitimate.

I would appreciate some links to the appropriate parts of the Microsoft website where I could purchase a key if this is possible.

Thanks in advance.

Hello neubejiita, and welcome to Eight Forums.

Do you have a legal copy of XP (sp3), Vista, or Windows 7?

If so, then you will need to install and activate one of them, run the "Windows 8 Upgrade Assistant" in it up to step 14 in the tutorial below to purchase the Windows 8 upgrade product key, then you will be able to legally clean install or upgrade install Windows 8 and activate it.

If not, then you will need to buy a "System Builder" copy of Windows 8 from any online or brick & mortar retail store instead.