Ubuntu 8.10 Network connection problem

I am completely new in Linux (and Ubuntu, obviously).
I had 8.04 for something like 4 days and then upgraded to 8.10
But I can’t connect to the internet! The network icon has disappeared from the taskbar!
What am I doing wrong?
Answer #1
Check your network settings to make sure it’s not disabled.
Answer #2
It’s not. :S