Assuming that you are using a dynamic IP address assignment via your provider, go to the network configuration (control panel) and re-initialize your NIC card. Look and see if the connection is active and activate it if it is not.
What is the output of kudsu -p? Does it show your NIC card loaded as a module? Does ifconfig show an ip connection, say 192.168.2.100?
I assume this is a cable internet connection?