sudo sh -c "echo 'deb http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu jaunty main' >> /etc/apt/sources.list" sudo sh -c "echo 'deb http://ppa.launchpad.net/kubuntu-ppa/staging/ubuntu jaunty main' >> /etc/apt/sources.list"

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8AC93F7A

sudo aptitude update && sudo aptitude dist-upgrade

sudo aptitude install kubuntu-desktop

aptitude

But if you normally use apt-get, than use that instead of aptitude!

If you still want to continue, you can add these repositories by running the following command in a terminal:Then add the GPG key:And finally to upgrade to KDE 4.3:Or, if you don't have KDE installed already:It is better to use '' because if you don't like your new desktop you can simply uninstall the packages with all its dependencies and you are back to the system state where you were before. That is not possible directly with apt-get (or synaptic etc.) (works with --purge but I find aptitude better, but let's not get into a pointless discussion).