Changing Drive Letters. _This one thing has always driven me crazy. I like to have C as the system drive, D as the CD-ROM or DVD and E as the data drive, but sometimes, I get it wrong when I install. Here’s how to fix it._
To change the default letter assignment for drives:
# Right click [My Computer]
# Click [Manage] to open the Computer Management Console
# Click on Storage and then click on Disk Management in the left pane
# In the top or lower right pane, right click the disk you want to change.
Fixed drives appear in the top and bottom pane. Removable drives appear in the bottom pane unless they have media inserted in which case they appear in both the upper and lower pane.
Select [Change Drive Letter and Path]
Click [Change]
Select the new letter from the drop down list box and click [OK]