What exactly is the error you are getting when you try going to sites? If you can get internet with Konq, you aren't having firewall issues. To find out more, you will want to use the command-line, but it won't hurt, I promise. Open a terminal, and then type 'firefox'. This will of course start Firefox, but it will display everything that is going on in the background. Go to a site or two, and see what errors are displayed in the terminal.