wireless network question

Ok. I think I have an easy one, but search's are making me more confused.
Two days ago, I set up a Belkin wireless router. It was easy. After set up, my iBook found the router, and I was able to connect wireless. Today, I get home, and I couldn't get on the internet. When I do the Network Diagnostics, I can see my network on the Airport list, but it asks for a password. I never used a password, before?? When I did my router setup, it never asked to create a password. I have a limited, but fairly broad, understanding of this stuff, and don't know where to start???

 

Nevermind. Now it's working. Tomorrow's project is figuring all this out.