[barksdale]

I have a Logitech 5.1 surround system I am selling to someone and I want to show him all the speakers work.
 
Unfortunately sound is not coming out of all the speakers...
 
The right rear and right front speaker there is sound.
 
There is bass from the subwoofer.
 
The Center speaker works if the matrix button is on.  It doesn't if it is off.
 
I am using onboard sound.  I have 6 audio jacks in my motherboard.
 
I put black in black, green in green, and orange in orange.
 
I am using Realtek HD Audio Manager.
 
I have tried Quadraphonic, 5.1, and 7.1.  None of them make a difference.
 
thanks