How to change, add, or remove a drive letter

1. Open Computer Management by clicking the Start button , clicking Control Panel, clicking System and Security, clicking Administrative Tools, and then double-clicking Computer Management.  If you’re prompted for an administrator password or confirmation, type the password or provide confirmation.
2. In the left pane, click Disk Management.
3. Right-click the drive that you want to change, and then click Change Drive Letter and Paths.
4. Do one of the following:
   • To assign a drive letter if one has not already been assigned, click Add, click the letter that you want to use, and then click OK.
   • To change a drive letter, click Change, click Assign the following drive letter, click the letter that you want to use, and then click OK.
   • To remove a drive letter, click Remove, and then click Yes to confirm that you want to remove it.

Cr. http://windows.microsoft.com/