? You do not have to install Programs to the default "Programs Files" folder which is at the drive where you install the OS. C: in your case ? You can create a folder at D: e.g. named "My Programs" or other more descriptive names, like " Games Programs", and create sub folders within with names of the actual progam. When you install progams, just browse/point to the folder when you are asked where to install the program to.

? BTW, what do you use D: for ?