I'm going to make this as short and simple as possible.

I have Windows 7 CD. Installed it on current drive long time ago. When windows 10 came out, I upgraded for free. I don't have Windows 10 installation and would like to have Windows 10 on new drive. I even have a Windows 10 Enterprise key (not sure if it works. won in a giveaway here some weeks ago). I want a fresh start, windows only on new drive and make old drive as temporary secondary drive and move whatever I want to move onto new and once done, throw old drive away.

My question is, how can I do what I explained above? The windows part, I'm pretty sure I know how to do secondary drive.