Copie e cole no seu arquivo "/etc/apt/sources.list" e, em seguida, execute
Isso não incluirá mais o software do hardy , mas fará o trabalho.
# deb cdrom:[Ubuntu 12.04.4 LTS _Precise Pangolin_ - Release amd64 (20140204)]/ dists/precise/main/binary-i386/
# deb cdrom:[Ubuntu 12.04.4 LTS _Precise Pangolin_ - Release amd64 (20140204)]/ dists/precise/restricted/binary-i386/
# deb cdrom:[Ubuntu 12.04.4 LTS _Precise Pangolin_ - Release amd64 (20140204)]/ precise main restricted
deb-src http://mirrors.gigenet.com/ubuntuarchive/ precise main restricted #Added by software-properties
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://mirrors.gigenet.com/ubuntuarchive/ precise main restricted
deb-src http://mirrors.gigenet.com/ubuntuarchive/ precise multiverse universe #Added by software-properties
## Major bug fix updates produced after the final release of the
## distribution.
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://mirrors.gigenet.com/ubuntuarchive/ precise universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://mirrors.gigenet.com/ubuntuarchive/ precise multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://mirrors.gigenet.com/ubuntuarchive/ precise-security main restricted
deb-src http://mirrors.gigenet.com/ubuntuarchive/ precise-security restricted main multiverse universe #Added by software-properties
deb http://mirrors.gigenet.com/ubuntuarchive/ precise-security universe
deb http://mirrors.gigenet.com/ubuntuarchive/ precise-security multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu precise partner
deb-src http://archive.canonical.com/ubuntu precise partner
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu precise main
deb-src http://extras.ubuntu.com/ubuntu precise main
deb http://archive.canonical.com/ precise partner
deb-src http://archive.canonical.com/ precise partner
#deb http://hu.old-releases.ubuntu.com/ubuntu/ hardy universe
#deb-src http://hu.old-releases.ubuntu.com/ubuntu/ hardy universe
#deb http://hu.old-releases.ubuntu.com/ubuntu/ hardy-updates universe
#deb-src http://hu.old-releases.ubuntu.com/ubuntu/ hardy-updates universe
deb http://mirrors.gigenet.com/ubuntuarchive/ precise-updates restricted main multiverse universe
deb-src http://mirrors.gigenet.com/ubuntuarchive/ precise-updates restricted main multiverse universe #Added by software-properties
deb http://mirrors.gigenet.com/ubuntuarchive/ precise-proposed restricted main multiverse universe
Em seguida, execute
sudo apt-get update
sudo apt-get dist-upgrade && sudo do-release-upgrade