my main idea is that the power to your spkrs is out of whack with what they can take - or that they are blown.
Really we could do with a better idea of what you mean - could you put a mic to them and send us a little wav? (j/k!)
But you could tell us more about stuff like the guy ^ said.
Also maybe it's possible there's a software issue or your machine is overloaded in some way - you did say second machine - so I guess your first one plays fine and what might that be - can you swap components to find the one that doesn't work? If you plug headphones in is the noise the same?
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS