Neutac speakers weird problem :S

[topps999]

well today i booted my computer all was fine, playing counterstrike, fine, then i restarted it and noticed my speakers (neutac 5.1 home theater system) we're making a kind of static shock noise, i unplugged them it was fine, then i put the cable from the speakers to my soundcard on to my case (a plain silver aluminium case 1 glass windows with chassis fan in the center) and the noise came back increasingly louder, i tryed all the adjustable knobs, (woofer, center, sourround, master) none of them changed it, so i plugged them back in and rebooted again, same problem... could anybody suggest why this is or anything , i thought they mite be picking up a connect from something but i checked all the wires outside the case and nothing is now touching it... could someone please help thanks .topps.