GERENCIADOR DE PACOTES

O GERENCIADOR DE PACOTES DO MEU DESKTOP, eu uso o ubuntu 12.04,NÃO ESTA RESPONDENDO, QUANDO EU CLICO NO ÍCONE ELE SÓ INICIA MAS QUANDO OS GRAFICOS APARECEM ELE DESLIGA,SOME DA TELA, E NÃO CONSIGO INSTALAR NADA POR LA,E QUANDO EU CLICO NO ERRO APARECE ESSA MENSAGEM"E:linha mal formada 42 no arquivo de fontes/etc/apt/sources.list" grato desde ja..

poste a saida deste comando:

cat /etc/apt/sources.list

para a gente ver como está seu sources list.

verifica a linha 42 no arquivo /etc/apt/sources.list

root@luis-M61PMV:/home/luis# cat /etc/apt/sources.list
deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)]/ precise 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.

## 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.

## 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.


## 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.ubuntu.com/ubuntu precise universe multiverse restricted main
deb-src http://archive.ubuntu.com/ubuntu precise universe multiverse restricted main #Added by software-properties
deb http://archive.ubuntu.com/ubuntu precise-updates universe multiverse restricted main
deb http://archive.ubuntu.com/ubuntu precise-proposed universe multiverse restricted main
deb http://archive.ubuntu.com/ubuntu precise-backports universe multiverse restricted main
deb http://archive.canonical.com/ precisepartner
deb-src http://archive.canonical.com/ precisepartner
deb http://archive.canonical.com/ precise partner
deb-src http://archive.canonical.com/ precise partner
root@luis-M61PMV:/home/luis#

presta bem atenção no que eu vou te falar!

vai no terminal


digite este comando gksu gedit /etc/apt/sources.list


e apague estas duas linhas

deb http://archive.canonical.com/ precisepartner
deb-src http://archive.canonical.com/ precisepartner

pois 1º é precise partner e 2º se você colocar o espaço vai conflitar com os repositórios abaixo, se trata de um repositório igual ao que está na parte de baixo.

dai salve e rode o sudo apt-get update

valeu Annakamilla,funcionou perfeito,muito obrigado mesmo, ja estava achando que teria que formatar meu pc novamente,abraço