Ei, nazeazeno, abra o Terminal e digite o seguinte código:
sudo gedit /etc/apt/sources.list
Agora, SUBSTITUA o conteúdo atual do arquivo aberto por este que postei aqui:
# Edgy Final Release Repository
deb http://br.archive.ubuntu.com/ubuntu/ edgy main restricted universe
deb-src http://br.archive.ubuntu.com/ubuntu/ edgy main restricted universe #Added by software-properties
# Edgy Security Updates
deb http://br.archive.ubuntu.com/ubuntu/ edgy-security main restricted universe
deb-src http://br.archive.ubuntu.com/ubuntu/ edgy-security main restricted universe #Added by software-properties
# Edgy Bugfix Updates
deb http://br.archive.ubuntu.com/ubuntu/ edgy-updates main restricted universe
deb-src http://br.archive.ubuntu.com/ubuntu/ edgy-updates main restricted universe #Added by software-properties
# Edgy Backports (new software versions, provided by the Ubuntu Backports Project)
# deb http://archive.ubuntu.com/ubuntu edgy-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu edgy-backports main restricted universe multiverse
#Ubuntu Commercial
# deb http://archive.canonical.com/ubuntu edgy-commercial main
Para concluir a solução, digite mais uma vez através do Terminal os códigos:
sudo apt-get update
sudo apt-get upgrade
Com isso sua lista de repositórios fica relacionada apenas a nova versão do Ubuntu, Edgy Eft (6.10).