Dodge, sorry that I let this fall through the cracks (just saw another post I missed too lol), are you in Windows 7? If so, when a sound is playing (or supposed to be playing) on a webpage, if you click on the sound button in your toolbar (the speaker) it should list "speakers" and "whatever web browser you're using", make sure both are turned up...
A lot of the time the speaker for the web browser will get turned down really low and when someone goes to tinker with the sound settings to turn it back up and the browser isn't playing anything more it'll just adjust the main volume versus the one for the browser, so the browser just ends up staying muted (or turned down low).