Just curious, what sound card
are you using. If it's an SB Live! then there should be no problem at all. Also, what kind of cable are you using? Where did you buy it?
Let me describe my setup:
-SB Live! value (all Live! cards are basically the same)
-cable: male phono jack to 2 male RCA jacks bought at Radio Shack
-volume properties: all sliders except main are set at full, main is a 1/3 so I can adjust more with my speakers.
I only bring these things up again because you really shouldn't have much of a problem doing this. Listening to my empeg via my computer is almost as big a use to me as it is in the car, and it works very well.
Good luck!
DiGNAN