You might also look into "parental control softwares" that lets you blacklist certain file extensions. For example, if you add .mp3, .avi, .doc into the blacklist, everytime someone tried to open up an mp3 audio file, an avi video file, or a doc document file, it would prompt the user to enter in the parental control password.
I am unsure as to which software can accomplish this task for you, but as a programmer, I know that this is something that is definitely possible. I would be surprised if it was not already made. If it's not already made... well then there's money to be made by someone.
Edited by -Wade-, December 02, 2013 - 01:30 PM.