Okay, I seem to have a similar problem here. Wondering does anyone know what the problem might be? When I click to play a song in itunes, it comes up but then doesn't play. Sound wise nor does it move as if it's playing. At this point, I'm sure I need a new computer soon as it's 7 years old but I'd really like to hold out as long as I can before I do that because I've no money. Iphoto recently deleted all my photos from the library (and won't even open the library) so at least I have my music backed up before this new glitch but I'm hoping there is a quick fix. Any help is appreciated.
https://discussions.apple.com/thread/4307934?start=0&tstart=0
https://discussions.apple.com/thread/4307934?start=0&tstart=0