I moved the location of my music to my external hard drive. Now itunes is say "The song ----- could not be used because the original file could not be found. Would you like to locate it?" Well I go to my external hard drive location and the song is there. I have tried to change the location back to my internal hard drive. But it says the same thing. At this point I don't know what to do. Half of my music is in the folders but I can not access them. What do I do???