If you followed my link above for Replacing a Sound Card, the first thing it says to do, after gathering your tools, is to remove the sound drivers and then follow the step-by-step procedure. It shouldn't be this difficult unless the sound card being installed is defective or has corrupt drivers.

Concerning the Audio Codec not showing up in Setup, keep trying...as the confus-ed one said. It may take a couple of tries to get going. Of course, you need to power off after each time...don't just hit the Reset button.

Anyway, keep us up on what's going on.