"Airport: Not Configured"

Hi,

I recently setup a new iMac by transferring my info from an older Mac Pro. I had been using Ethernet on the Mac Pro and had therefore, turned off the Airport. The problem is, on the new iMac, I cannot turn on the Airport - it displays "Airport: Not Configured".

I've successfully added an Airport interface in the Networks Pane, but it doesn't reflect in the airport icon on the menu bar. Also, the new Airport Interface wants to call itself "Airport 2" which suggests there's another one lurking in the background somewhere.

Help?

Thanks,
Jamie