The Windows operating system assigns a letter to all drives, partitions, logical drives and volumes. The letter is used to uniquely identify the drive when referenced by programs and different actions of the computer. All 26 letters of the alphabet may be used. By default, the internal hard drive is assigned "C:" with additional partitions of the drive typically assigned letters starting with "D:" and so forth. A drive may need to be remapped and assigned a new letter if the drive letters become mixed up or a specific program requires a specific drive letter.
Log-in to your computer as an administrator.
Click the "Start" menu button, click "Control Panel" from the right-side of the menu and click "Performance and Maintenance." Windows Vista users select "System and Maintenance."
Select "Administrative Tools," double-click "Computer Management" and select "Disk Management" from the left pane.
Right-click the drive you want to remap. Click "Change Drive Letter and Paths" and select "Change."
Click "Assign the following drive letter," select the drive letter you wish to use and click "OK."
Click "Yes" at the confirmation prompt to change the drive letter.