One thing i've done when it says that my computer is connected but the browser won't work is - If you have internet explorer, even if you don't use it, you load it up and try to get a website working. It will then come up with a message saying that it can't load the website and will give you some options. there is one that either says "diagnose" or "repair" or something like that.. You choose that and it will run through a bunch of things... 95% of the time it's gotten me a new IP address and will work out what the issues is and fix it..

Not sure if it will help you, but it's one option to try if you have IE.