@bassfisher: I must admit, I'm not sure how professional my point of view is. I've had problems with this issue = drive letter D must be assigned to CD / DVD, because the function of certain CDs / DVDs won't work otherwise. However, this may be old info and experience, not relevant in Windows 7+. If I remember correctly, I couldn't get Morrowind to play unless in D, to give one example.
As you most probably know, my intention is not to misinform, nor to make life harder, heh. Thanks for your reply, friends do give constructive criticism!