I diconnected the AC'97 front panel header from the mobo and connected it to the sound card. The front panel audio works, i.e. after connecting it to the new sound card, the mic and headphones I connected to it work fine.
I have absolutely no problems (hardware or software), driver issues, or even boot errors, and everything is perfectly fine. I just get a "Press F1 to boot" prompt that always says "Front panel audio not connected". How do I get rid of this annoying message (and prompt)?