You can hide partition drive letters so that users can only run programs if they know the full path to the executable.  You can still access the contents of the partition, but you will not be able to browse or descend the folder structure.

Hiding drive C:\ (disk 1 partition 1)

hide.cmd:

@Echo Off
Echo select disk 1 > .\diskpartCommands.txt
Echo select part 1 >> .\diskpartCommands.txt
Echo Set ID = 17 Override >> .\diskpartCommands.txt
Diskpart /s .\diskpartCommands.txt
Del /Q .\diskpartCommands.txt

Unhiding drive C:\ (disk 1 partition 1)

unhide.cmd:

@Echo Off
Echo select disk 1 > .\diskpartCommands.txt
Echo select part 1 >> .\diskpartCommands.txt
Echo Set ID = 07 Override >> .\diskpartCommands.txt
Diskpart /s .\diskpartCommands.txt
Del /Q .\diskpartCommands.txt