MacBook Air wifi issues I bought a brand new MacBook Air from the apple store in Sydney last week, but no matter where I go to connect to a wifi source, it never connects. Wherever I try an exclamation mark shows up and I don't know why this is. I've tried a few things in the system preferences but still unsure. Can someone please help me??
I wrote an extensive post on MacBook Air wifi issues:

https://apple.stackexchange.com/a/70605/34078

It's not exactly your symptoms, but a good start. 

Take a look at the wifi equipment you are trying to attach to. If you can't still get a connection after reading my previous post, take the MBA back to the Apple store and see if you can connect there. If you connect, the issue probably sits with your wifi router. If you cannot connect, it's the laptop.