Airport worked, now it doesn't?

So I purchased my MacBook about a month or so ago and when I got it, AirPort worked fine; now it doesn't detect networks when it defintely should, and when I do get lucky and it detects it for two seconds, it asks me for a password when there is no password.

Should I take the airport card and put it back in? It reads that it's in there correctly and displays all the information. Any help is appreciated because this is getting annoying now.

You can not remove the airport card and put it back in. Your MacBook is not a desktop PC.

Has anything been changed lately? New router? New provider? Updates? New location? Can you get on the NET using an ethernet cable?

Regards.

Well, I have actually changed locations but it doesn't work at home or at college and yeah, I can get onto the internet through an ethernet cable.

Here's a pic if it helps:



Reason why isp, internet, and server are green is because I'm hooked up via ethernet.