5.1 help please

I dont know if this is the right place but can someone help me on my 5.1..
hear it is...My front left and front right work and my rear left and rear right work..so does my center but for some reason my sub does not work... can anybody help me on this?...
SPECS..
sb live 5.1 sound card
dont know what speakers cus i ripped up the box..
think thats all you need to know.. if not please tell me
:bawling: :bawling: :confused: