Connected to internet but Chrome and firefox not working

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http://askubuntu.com – I upgraded to ubuntu 11.10 a couple of days ago. chrome and firefox were working fine for a day then they just stopped. I know there's nothing wrong with the wifi because I can access it on my phone and because when I added a file to my dropbox account it told me. Chrome and ff say the server refused the connection. Pinging Google.com returns some data. (HowTos)