Bagaimana Cara Upgrade Ke Hwe 12.04.5?

Sistem saya:Dell OptiPlex XE2 baru dengan 12,04 pra-instal oleh Dell.

Saya menerapkan semua pembaruan keamanan melalui manajer pembaruan. Sekarang Update Manager memberi tahu saya ini:

Saya mengklik tombol Tingkatkan dan saya mendapatkan kesalahan ini:

Bagaimana cara memperbaikinya dan meningkatkan sistem saya ke 12.04.5 terbaru?

/etc/apt/sources.list

# deb cdrom:[Ubuntu 12.04 _Precise_ - Build amd64 LIVE Binary 20130203-13:50]/ precise main

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise main restricted

## 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://us.archive.ubuntu.com/ubuntu/ precise universe
deb-src http://us.archive.ubuntu.com/ubuntu/ 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://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ 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://security.ubuntu.com/ubuntu precise-security main restricted
deb-src http://security.ubuntu.com/ubuntu precise-security main restricted
deb http://security.ubuntu.com/ubuntu precise-security universe
deb-src http://security.ubuntu.com/ubuntu precise-security universe
deb http://security.ubuntu.com/ubuntu precise-security multiverse
deb-src http://security.ubuntu.com/ubuntu 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

## Uncomment the following two lines to add software from Ubuntu's
## 'extras' repository.
## 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

/etc/apt/sources.list.d/precise-dell.list

deb http://dell.archive.canonical.com/updates/ precise-dell public
deb-src http://dell.archive.canonical.com/updates/ precise-dell public

/etc/apt/sources.list.d/precise-oem-sp1.list

deb http://oem.archive.canonical.com/updates/ precise-oem-sp1 public
deb-src http://oem.archive.canonical.com/updates/ precise-oem-sp1 public

Jawaban yang Diterima:

Anda telah mengaktifkan pembaruan keamanan, tetapi bukan pembaruan reguler.

Terkait:Partisi Menghilang Setelah Power Loss Saat Menginstal di Ubuntu?

Pastikan untuk mengaktifkan pembaruan yang tepat di sumber perangkat lunak Anda seperti yang dijelaskan di halaman wiki ini.

Kemudian, ikuti kembali petunjuk di https://wiki.ubuntu.com/1204_HWE_EOL_OEM