nforce sound problem, no 5.1 sound

nforce sound problem,need help

I have just recently bought a set of altec lansing 251 speakers and I have had no luck getting the rear or center speakers working. The sub and front sound great. I have the newest driver for the onboard sound from windows update and have been through many settings within the control panel for the sound apu.
I have been using ati's dvd player and no 5.1 sound, does ati's dvd even support it ?
I am to the point that I think I must not be running application that puts out 5.1 sound. How could I test it?

My motherboard is an Abit nv7-133r .

I fixed it.

If I might ask, what did you do to fix it? Someone may have that problem in the future and it could save them some time.

After many hours of fooling with this I found
http://www.nforcershq.com/forum/index.php
This site helped me get all the speakers working and helped me understand what the nforce was about.
My findings are: Keep reading many fourms, this one first, post often and don't give up, remember it's only a computer or so my wife says. CRB

Same Problem

I have the same problem with the Turtle Beach Santa Cruz and Altec Lansing 251s but I the speakers work fine for games like Unreal Tournament 2003. Once I start playing a DVD though the rear speaks hardly work at all.....they just hiss a lot and let out a small sounds from the movie. This is all with thems witched to 6 channel mode. If I turn the switch on them to 2/4 channel then the rear speakers work a lot better with DVDs but it does not sound nearly as good in Unreal Tournament 2003. Could anyone please help me?!?!!?