Can I download the IW5 base game to D hard drive instead of C drive?
Installing games on the same drive as the OS is always a bad ideea.So for example i have one drive just for games.exemple : G:/Games/Steam .
To asnwer ya question , it doesn`t matter what drive it is . If u have your games on D , install MW3 there.
Yes you can, you'll need to create a new steam library (possible in steam settings) for that drive if you don't already have one. Then when starting the download it will ask you which library to want to download the dedi server to.