Applications :: Not Able To Load Music Into ITunes On G4

I have a problem with my ITunes, the file shows up when clicked on to play, but the sound does not come out of the speakers. The song is highlighted in the juke box, the play button show a darker grey, but the song does not play, nor does the time advance or the pause button does not appear. TV shows, that I have downloaded for my daughter from the ITunes store, play video fine, but again, no audio. I have the up to date Quickplay, the audio level on ITunes is on max, the stereo speakers play on the internet fine. The system is a g4, with the current ITunes updates. I am still able to load music into ITunes, and transfer the music on to my IPod, my daughters IPod ano, and my wife's IPhone.