Sudo gedit /etc/apt/sources.list
séléctionner tout et remplacer par ça :
deb http://archive.ubuntu.com/ubuntu/ edgy-backports main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ edgy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu edgy-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ edgy main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ edgy-proposed restricted main multiverse universe