Often times, the online sites have the volume only set to 25 or 50%. Since I tend to keep my sound low, most of the time this leads to there apparently being little or no sound. Once I move the slider to full volume, no problem. For some odd reason, this is not as big a problem for Windows Media Player. Perhaps it's because the volume controls are more noticeable than they are for the online players. Could this be what's happening to you?