You can change the drive letter of any disk in Windows 8 as per your requirements. However, it is not recommended to change the drive letter of the default C: as some programs which are running depends on it and they might not work properly after you change it. You also have to note that you cannot assign same drive letter to two different drives. A drive letter must be unique for a drive. To change the drive letter of a disk drive in Windows 8, follow the below given steps:
1) Press Windows key + X and select “Disk Management”.
2) Right click on the disk icon for the disk for which you want to change the drive letter and then, click on “Change drive letter and Paths…”
3) Select the drive letter in the “Change drive letter and Paths” dialog box and click on “Change”.
4) Select the desired drive letter from the drop down menu and click on “OK”.
5) If you get a dialog box “Some programs that rely on drive letters might not run correctly. Do you want to continue?”, then, select “Yes”.
6) Click on “OK”.