Internet Access problems in Fedora Core 4

Hi

I m new to the linux-unix world. I m facing a problem while i try to access internet on Fedora Core 4.

I m using an ethernet LAN card to access the internet. I behind a proxy. I m using 3com Etherlink XL 10-100 card. As i enter a url ( any url) in firefox web browser in kde, i get an error message to the effect of " cannot find the address, please check the address." I saw the same problem being reffered to on another forum, somebody suggested that the system in this case is not able to see the internet. I did not understand what they suggested there, perhaps that suffices to say that i m new to this unix-linux world.

I did manage to activate my LAN card. How ever the browser doest open any page to view. The same LAN card works fine on XP as i have a dual boot system. Is it something to do with the connection settings, loopback interface, browser settings, the proxy that my isp is using to allow security or is it something more complicated.

Please suggest a solution, im struggling to resolve the issue. Its not a good feeling at all.

Regards j,aldin