Headset vs Speakers

[Sacraed]

I've got a strange problem. My headset will not work no matter where I set my defaults to 'headphones'. However, if I unplug the headset's black plug from my SB back panel OR my MB back panel and plug it into my speaker EVERYTHING changes so that I can't use my speakers ever again but the headset WILL work. I installed the SB card hoping to solve the problem but guess what? It's still here. How can I set up my system so that I can switch back and forth between headset and speakers, and how do I get the headset to work just to begin with?

Sacraed,
Befallen Server,