I am helping my brother-in-law try out Ubuntu. He has a Compaq Presario 5430 and it will not connect to a wired network. I am running Ubuntu with live cd before installing but cannot connect. The icon at the top of the desktop is NOT "x" out. It appears to be connected yet when I fire up Firefox it will not go to any page. I'm sure this is a relatively simple fix but I do not know where to begin. Any help would be appreciated.

EDIT: I failed to mentioned the live cd is Hardy. I also tried PCLINUXOS and Linux Mint 4.0 with the same results.