Internet Settings!

I think I screwed up my internet settings early on in the game, and have not been able to connect to wireless networks for some time now. I want to reset my Internet Settings, once and for all, all of them, but have been unable to do so. Any suggestions?

If that is impossible, here are the particulars that I want to do. 1) I want to get rid of the VPN Icon on my bar. 2) I want to be able to connect to wireless networks and access the internet with Airport.

Often I can access the Airport Network, and the first two lights in the Diagnostic are green, but when it gets to Network Settings it's red all the way down.

Any help would be much appreciated, thanks!

PS - I have a new Powerbook. OS X 10.4.2