To connect your computer to Internet is very easy in Ubuntu.First go to application – accessoriesterminal. Inthe terminal type “sudo pppoeconf” and hit enter.Then It will ask you a few question ,you have to answer it in yes or no.(My suggestion in every questions hit yes ).when you are asked to give the username and password for your connection ,submit it and you are done. Then to start internet connection type “sudo pon dsl-provider” in a terminal . To disconnect your internet connection “sudo poff dsl-provider”