easiest way... create a symbolic link on your c-drive (named as the original location) that points to your new location.
So, let's say it used to be c:\drumFiles, which you copied to e:\drumfiles, open a command prompt, and type the following command:
mklink /d c:\drumfiles e:\drumfiles
Make sure the C:\drumfiles directory isn't on your drive anymore before you run the above command. If your names included spaces, put the location in quotes (eg mklink /d "c:\drum files" "e:\drum files")
Your pc will act as if the files are still where they used to be, while in reality they are stored in their new location.
So, no need to tell sonar where to find them, as for Sonar, they haven't moved...