Ubuntu-fr

Disparition de corbeille, solution complétée:
Aller dans Applications, puis Outil système, puis Préférences, puis Advanced Sittings. Dans Advanced Sittings, cliquer à gauche sur Desktop et à droite, activer les icônes voulus, par exemple, "trash icon visible on desktop"
[img=Advanced Sittings]Capture du 2012-12-22 22:16:32.png[/img]

Problème résolu ainsi:
Saisir dans console: sudo gedit /etc/apt/sources.list
J'obtiens cette liste de sources:
deb cdrom:[Ubuntu 11.04 _Natty Narwhal_ - Release i386 (20110427.1)]/ natty main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
## Major bug fix updates produced after the final release of the
## distribution.
deb http://fr.archive.ubuntu.com/ubuntu/ natty-updates main restricted universe multiverse
deb-src http://fr.archive.ubuntu.com/ubuntu/ natty-updates main restricted universe multiverse #Added by software-properties
## 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.
## 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.
## Uncomment the following two lines to add software from the 'backports'
## repository.
## 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://fr.archive.ubuntu.com/ubuntu/ natty-backports main restricted universe multiverse
# deb-src http://fr.archive.ubuntu.com/ubuntu/ natty-backports main restricted universe multiverse
# deb http://security.ubuntu.com/ubuntu natty-security main restricted universe multiverse
# deb-src http://security.ubuntu.com/ubuntu natty-security main restricted universe multiverse #Added by software-properties
## 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 natty partner
# deb-src http://archive.canonical.com/ubuntu natty 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 natty main
deb-src http://extras.ubuntu.com/ubuntu natty main
deb http://archive.ubuntu.com/ubuntu natty main universe restricted multiverse
deb-src http://archive.ubuntu.com/ubuntu natty universe main multiverse restricted #Added by software-properties
echo deb http://download.virtualbox.org/virtualbox/debian natty contrib

j'ai supprimé  la dernière ligne cause du problème: "echo deb http://download.virtualbox.org/virtualbox/debian natty contrib"

echo deb http://download.virtualbox.org/virtualbox/debian natty contrib
puis saisir sur console:
sudo apt-get update && sudo apt-get dist-upgrade

Et tout est rentré dans l'ordre.