My computer speaker setup is messed up!? whats wrong!? please help!?

[Mike]

I have 3, 2 piece speakers (6 speakers all together for surround sound) and they worked for like a week and then they all stopped. Now only the 2 front left and right speakers work. The subwoofer,center,and back speakers don't work.
The center and 2 back speakers play through the 2 front speakers now!
how do i fix this.
All the speakers work perfectly, just not on this computer.
can anyone help??

[theS]

you have to go into your sound card settings and switch from stereo to surround sound so change it from 2.1 to 5.1 and make sure you have dolby pro logic on and not 5 channel stereo