Internet Never works in full installation - But works great in Live CD

[shahadat]

I'm very new in GNU/Linux.

My UBUNTU works great with the live-cd but after installation internet is not working at all.

I've tried 32 bit 8.04 & 8.10

My network Adapter is : Intel(R) 82566DC Gigabit Network Connection.

Someone please help! I so want to use ubuntu..:(

My other two friends are also facing this very problem..

[mikewhatever]

More info needed. Post the outputs of the following:
ifconfig
sudo lshw -C network
cat /etc/resolv.conf

What exactly doesn't work? What does?