did you try headphones?
The way most of these speaker sets work these days is your audio out from your card will take the signal from your card to your Sub(or a left or right channel but, usually the Sub) and then from there the signal from your sound card is split into the the appropriate channels. You said the speaker worked great before you moved your machine. Now your onboard and PCI audio are crap. I suppose it's possible your hardware crapped out on you but, I would keep investigating. Do a google search on your model and see what comes up in the FAQ pages. Try some headphones
