Just keep your CD audio and your computer audio seperate in your head.
If you have a "normal' CD in your drive and you play the music on it, that's CD audio.
If you have a CD full of MP3's in your drive and you play the music on it, that's computer audio.
Same end result, different process. Only the CD audio goes through that audio cable. The computer "audio" goes through your IDE cable.
The audio cable normally needs to be plugged into your sound card, so that CD audio gets input into your computer and you can then treat it like any other form of computer audio.
Or, you can be cool and never use audio CD's any more.
