il seguente file dovrai editare /etc/apt/sources.list

deb-src http://archive.ubuntu.com/ubuntu/ edgy main restricted universe multiverse
deb-src http://security.ubuntu.com/ubuntu/ edgy-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ edgy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ edgy main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu/ edgy-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ edgy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu edgy-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu edgy-backports main restricted universe multiverse

Se questa operazione non farai, pochi aggiornamenti scaricherai!