Yah what u can do is (ive done this before) go to the dollar store and buy a 3.5 mm headphone jack to left(white) and right(red) rca connector.
Like this...
Next move your whole system to your computer (or just get a really long cable) and connect the headphone part....
and plug that into your audio out port of your soundcard most often colour coded green.
Next take the left and right rca connector...
and plug these into your stereo's AUX, CD, VIDEO 1;2;3, TAPE etc...
shown in the bottom left hand corner...
Connect your speakers to the receiver and then plug the reciever in to the wall. Turn your reciever on and set it to AUX, CD, VIDEO 1;2;3, TAPE whatever you connected the PC to.
Play a song on the computer with the computers main at half and the wave at full volume. Now you can adjust the volume on your stereo receiver to what you want to listen to it at.
ENJOY BLASTING YOUR MUSIC

!!