I have installed Windows 8 RP over 7...

So it all started a week ago, and I was using my Dev machine to install 8 but I didn't partition. All I have is the Windows 7 Product key on the side, Home Premium. Can I use it to upgrade?

Yes,, I did it and it works. Here is how: http://www.eightforums.com/tutorials/2234-upgrade-install-windows-7-vista-windows-8-a.html?filter

HTH.. Jeff