"No AirPort Card Installed" Message after PMU reset

My battery memory time was getting shorter and shorter, even after a full re-charge (less than 50 minutes). Apple Care suggested that I do a PMU reset and then recalibrate the battery. After I did that my AirPort icon has disappeared, and when I try to use Airport Setup Assistant, I get a message that says "No AirPort Card installed."

Yikes - any thoughts about how to get my AirPort working again?