From Wikipedia: In computing, drive letter assignment is the process of assigning alphabetical identifiers to volumes. Drive letter assignment allows multiple highest-level namespaces. Drive letter assignment is thus a process of using letters to name the roots of the "forest" representing the file system; each volume holds an independent "tree" (or, for non-hierarchical file systems, an independent list of files).
After upgrading computer system or connecting multiple hard disks. If you want to bring order out of chaos and reorganize your drives in a certain way, change letter of drive can be the most effective way.
New added hard disk may not be recognized by the computer and thus can’t be accessed. At this moment, the usual solution is to assign a drive letter to it. Then, it can be reached.
Some other situations when you have to change drive letter:
1. Connect one PC to another one.
2. Upgrade the drive and the new drive letter can’t be changed to the previously used drive.
3. The drive has been hidden so that we can change drive letter to show it.
4. Reform system and the drive letters changed.
How to create a disk image?
Disk Management assign drive letter
Partition Assistant Change Drive Letter
Step1. Right click the volume you want to rename drive letter and select “Change Drive Letter and Path…”
Step2. Choose “Change” to change drive letter in the pop up window.
Step3. Select new drive letter for object drive.
Step1. Right click aim partition and selctc “Advanced” – “Change Drive Letter”.
Step2. Choose a new drive letter for the partition.
Step3. Preview the partitions layout and click “Apply” on upper left to assign letter to drive.