You can Change Drive Letter of any Drive in your Computer according to you. Drive Letter A and B already reserve for Floppy Disk . if floppy drive not install then you can assign A and B drive letter to your Drive .
1. Click on Start Menu , then Right-Click on Computer then Click on Manage .
2. On the Computer Management Windows Click on Disk Management then Right-click on Driver Which you want to Change Drive letter and then Click on Change Drive letter and Path.. .
3. Now Click on Drive Letter C: and then Click on Change... . .
4. Now Click on Assign the following drive letter radio button then Click on Drive letter Drop-down menu and select drive letter then Click on OK .
5. Click on Yes to Next prompted windows , and then Close Computer Management windows .