My computer thinks its speakers are rear speakers for a surround sound. please help?

I have a bose companion 3 speaker system hooked up to my windows 7 alienware desktop. My problem is they sound like junk. My computer thinks i have a surround sound and it acts like they are the rear speakers. when i change it off of surround sound mode and back to stereo mode, They wont work.

Your computer should have separate speaker jacks - 1 for the front pair, 1 for the rear pair, 1 for the center, and 1 for the subwoofer.Be sure you plug the speakers into the "front" jack.(although they may still sound like junk - Bose speakers really aren't that great despite how expensive they are.)