No bass option in sounds

I just got a computer from my father and I have a simple speakers setup with two small speakers and a small sub woofer. With the new computer I cannot hear anything coming out of the sub woofer, when I try to change the set up in sounds, the only option that comes up is for a basic two speaker stereo setup it is not giving me an option to change the set up to reflect what I actually have. I am running Windows 7 and the sound card is a VIA AC97 Enhanced audio controller. Please help out I don't want to have to take it back to him after just getting it. Thanks

My speakers are a 2.1 and they are set up just like that one cord plugged into the green speaker part but the sub woofer get little to no sounds and when I go to configure my setup in the control panel I am not given an option to set it up with the sub woofer it only shows the two side speakers. The sound card was acting funny and he moved it to a different spot because it was acting funny with a USB port, when it was in the other spot it identified the sub woofer in the configuration sections of sounds and now it only shows the setup for the two speakers and nothing more. I know that probably sounds confusing but it is the only way I can think of the describe the problem, any more help would be great. Thanks

Great thank you.