You can easily change the drive letter for partitions with Partition Resizing Software
There are three ways to start the Change Letter operation:
a. Click Partitions in the top menu » click Change Letter
b. Click the button Label in the Tool Bar.
c. Right click the partition in the Partition list and then select Change Letter in the pop-up menu.
Tip: You should pay special care when changing the letter of a system partition as changing the letter of a system partition may cause your computer to not boot properly.