D:/ Drive is on another Hard disk.You're going to have to reinstall most applications, including Steam itself.
Steam games shouldn't be a problem though and once Steam is installed, you can point it to the directories of downloaded games. Assuming, of course, this is a separate drive from your OS drive. I'm not quite sure as your description is very unclear. "D:/Drive" refers to a location of a drive or a partition of a drive, not what the hardware is or what its function is.
D:/ Drive is on another Hard disk.