could you be clearer, those letter are just the same but in different order. But i think you want
1. Log on as Administrator or as a member of the Administrators group.
2. Click Start, click Control Panel, and then click Administrative Tools, double-click Computer Management, and then click Disk Management in the left pane.
3. Right-click the drive, the partition, the logical drive, or the volume that you want to assign a drive letter to, and then click Change Drive Letter and Paths.