Vista + Speaker problems

[allaboutheu]

I got a new computer w/ windows vista and am unable to get the audio to work correctly. I have a sigmatel audiocard and 4 logitech speakers (and 1 sub). The sub has a built in amp so all the speakers plug into it and then i plug the sub/amp into my laptop, this was never a problem with previous computers.

Now, I can only get sound out of 2 of my speakers (i believe front right and rear left) and my sub. When I open my sigmatel audio center it says 2/2.1 speakers which is clearly incorrect and probably why only 2 and the sub work. However there are no options to change this setting, it is not even clickable.

Does anyone else have similar problems? Have a great sound system and can't use it, its really frustrating, someone please help me out!