MacBook cannot connect to internet
I have a MacBook Pro running 10.8.2. As of yesterday, I can't connect to the internet via my wifi network. I know there is nothing wrong with the network, because my other devices are connecting just fine. My MacBook also works fine if I plug in the ethernet cable. Also, it is able to connect and work on nearby unprotected wifi networks, but I don't want to use these for obvious reasons.
The wifi status bar shows a full connection to my wifi network, but when I try to go to a webpage Google Chrome says: "This webpage is not available." At the bottom of the page it says: "Error 102 (net::ERR_CONNECTION_REFUSED): The server refused the connection." I know it's not just a problem with Chrome because Safari doesn't work and neither does any application that uses an internet connection.
Any help would be appreciated! Thanks!
MacBook Pro, OS X Mountain Lion (10.8.2)