MacBook wont find any wireless networks

[Mustard Chops]

I'm having a bit of a nightmare with connecting to any wireless networks on my MacBook.

If I click on airport in the menu bar there are no wireless networks listed - it's not finding any. Even in locations where I know there to be a wireless network that I've joined before (work, home, at a friends house)

Any ideas on how to troubleshoot this or is it a straight visit to the apple store?

 

[andalusia]

This happens to me constantly. I just key in the name of the access point I know and then the password and it connects, but it's piss annoying that it doesn't view the list first.

 

[bearcatrp]

It won't show anything if the wireless router is not transponding.

 

[andalusia]

It used to show, and shows on other laptops.