By default, the sound card is set for 2.1 channel output. The other lines would have a check mark next to mute in the volume control. If not, check the volume control provided by the sound card (Another speaker icon in the system tray). If that does not help, check if you have the Creative Soundblaster MB software installed on the system (You would also see it on the order)
there is no SB software on the PC. Is there a way to set the soundchip to 5.1 or 7.1?
And which speaker would need to be connected to which output jack?