Hello, I have a Logitech M530 5.1 Speaker set. I also have a 5.1 sound card. I have intsalled all the drivers and pluged everything correctly. I also went to the audio and sound icon in Control Panel and changed the speaker option to 5.1 sorround sound. But the center and two rear speakers don't work. The speakers don't have a fader control. Any suggestions on how to fix this problem would be greatly appreciated. Oh ya i am using a thunderbird 5.1 card. Its Plug and Play, supposedly. Its from Digital Multimedia.