no sound

IRealPro has been working fine for me on my 2007 MacBook running OS 10.6, and suddenly today when I hit the PLAY button, it won't play. The display of the time of the song begins to move for about 1/2 second, returns to zero, as if the song has been played and completed.

Hi Recently the sound on the app has stopped working. I can hear the first click on the 'count in' then it goes silent. I can see the chords being highlighted so it appears to be playing the song. I've tried all the usual things, like rebooting & reinstalling. The sound on my machine works...