Re: wrong driver installed ?
Welcome to CF!
There's a few points here...
1. You actually want the Windows installation on the smaller drive and then all of your data on the larger one. This segregates your core installation files and required files from personal files. If your PC pukes on you, then it's very easy to re-install Windows (or other OS) without having to hunt and find all your personal data.
2. Do NOT install Windows on D. It's not that you cannot do this, but the drive letters are more impacting to Windows than you might think.
Each program you install, you can specify where those data files should go (e.g. C:\Program Files). Depending on how small your main drive is, this could also be an option but you start to lose performance depending on the hosting drive's R/W speed among other factors.
How large/small are we talking about? You can easily maintain Windows and most all installed programs on a ~60-80GB drive. Then keep all your personal files on the larger secondary drive.
Humans are the only creatures that won't live up to the their potential. Give everything your all. When you die, die on E.
So I ask you, what do you intend to do now?