AirPort Application Disappeared Suddenly!

[SwampWitch]

Tonight I sent an email, closed up my MacBook, and put it down. When I went back to it, AirPort was gone! It wasn't an available option when I ran the diagnostics, and the icon wasn't on the bar at the top. After some digging, I saw a notice that the application wasn't on the computer.

Nobody else was home at the time.

I reinstalled it with the disks that came with the MacBook, but am wondering if anyone knows what could have happened?

Is it possible I have a virus or spyware? It's creeping me out a little.

Thanks in advance.