Setting up internet connection

[Don Jungk]

Hi,
I have just installed KUBUNTU 8.04.2 on a new computer. The installation 
seemed to go fine, but networking doesn't work. It is connected via cable to 
a dsl modem/router. Another computer connected to the modem uses Auto/DHCP 
for the IP address. If I look at network settings, it shows eth0 is enabled. 
If I open the "configure" window, it is set to DHCP, but the "Automatic" 
radio button is not selected. (none is selected) I can select it, but the 
window always reopens with no button selected. I can't access the internet, 
nor can I see the other computer on the network.

According to the manual, it should just work with no configuration (as I have 
seen in other distributions)

Any ideas?

Thank you for your time,
Don