hey, i just upgraded my pc, and am using an asus p5b with its onboard sound.
i hooked up my 5.1 system analog to the onboard soundcard, and the test confirms that all the speakers are setup and working properly, but i cant get the center and rear channels to work when the signal isnt in 5.1. im looking for something like a sound wrap type feature, where it remixes a stereo signal to 5.1 so i can hear out of all the speakers.
Ive also got the P5B-D, with an analogue 5.1 sys, and i also had dramas getting it to work properly.
Try the latest drivers.
At the end of the day my sound is now working 100%, although i had to reinstall and replug things in 100 times
Im assuming ur using the 3 plugs? centre, rear, and side/front woteva?
Using the windoze sound thingy, select the 5.1 speaker config.
Just keep playing around with it, its a PAIN but it will work.
Also make sure in the asus sound thingy u set it to 'cinema' for EVERYTHING exept music... when u select 'music' setting. Its a pain i know, but music can sound a little odd on the cinema setting... esp the bass... it comes and goes. very odd.