В /etc/apt/sources.list должно быть что-то вроде
deb http://archive.ubuntu.com/ubuntu/ hardy main restricted
deb http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted
deb http://archive.ubuntu.com/ubuntu/ hardy universe
deb http://archive.ubuntu.com/ubuntu/ hardy-updates universe
deb http://archive.ubuntu.com/ubuntu/ hardy multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-updates multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-security multiverse
deb http://ppa.launchpad.net/lxde/ubuntu hardy main
deb http://ppa.launchpad.net/abiword-stable/ubuntu hardy main
deb http://ppa.launchpad.net/transmissionbt/ubuntu hardy main
deb http://ppa.launchpad.net/stemp/ubuntu hardy main
deb http://ppa.launchpad.net/k-belding/ubuntu hardy main
deb http://ppa.launchpad.net/midori/ppa/ubuntu hardy main
deb http://ppa.launchpad.net/webkit-team/ppa/ubuntu hardy main
deb http://ppa.launchpad.net/klaus-vormweg/ppa/ubuntu hardy main
deb http://ppa.launchpad.net/alsa-backports/ppa/ubuntu hardy main
deb http://ppa.launchpad.net/hardybleed/ppa/ubuntu hardy main
# deb http://ppa.launchpad.net/c-korn/vlc/ubuntu hardy main
deb http://ppa.launchpad.net/pidgin-developers/ppa/ubuntu hardy main
deb http://ppa.launchpad.net/adrian5632/ppa/ubuntu hardy main
deb http://ppa.launchpad.net/chmsee/hardy/ubuntu hardy main
deb http://packages.medibuntu.org/ hardy free non-free
deb http://archive.infralinux.org/infralinux hardy-backports main
deb http://apt.wicd.net hardy extras
deb http://download.virtualbox.org/virtualbox/debian hardy non-free
deb http://wine.budgetdedicated.com/apt hardy main
up
Кусочек из моего старого /etc/apt/sources.list:
#Standard Ubuntu Repository
deb http://archive.ubuntu.com/ubuntu/ hardy main restricted
deb http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted
deb http://archive.ubuntu.com/ubuntu/ hardy-security main restricted
deb http://archive.ubuntu.com/ubuntu/ hardy universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-updates universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-security universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-proposed restricted main multiverse universe