How to change a computer hard drive letter
Unlike optical and removable drives, the drive letter of a hard drive cannot be changed. If you want to create multiple drive letters for a single hard drive, you must partition the hard drive into multiple segments. However, this only creates multiple drives letters in sequential, alphabetical order, such as C:, D:, or E:. More plainly, you cannot take a hard drive that has been automatically assigned the drive letter D: and change it to an alternate letter such as K:.