at the bottom of the Youtube video is a bar showing the progress of both Download and Play (which gradually overlaps download).
Start by checking Play lags behind and does not catch up to Download.
If it does, the music will tend to stop. As Beachy advises, this could be caused by the speed of your internet connection. Alternatively you could be running another application that intermittently hogs your pc.
You might also check you have the latest Flashplayer.
Good Luck - Keep us posted.
message edited by Mike Newcomb