Bien, vamos a ver como podemos activar los repositorios:

Vamos a la Konsole y ponemos lo siguiente:

sudo pico /etc/apt/sources.list/

Nos saldrá un archivo (sources.list), con repositorios (los oficiales), bien, pues deberemos quitar de todos los que tengan un “deb” al principio la almohadilla “#”, después pulsamos Control + Z y guardamos el documento (OJO: si no haceis el comando con sudo no os dejará modificarlo).

Os quedará algo así:

deb http://es.archive.ubuntu.com/ubuntu/ edgy main restricted
deb-src http://es.archive.ubuntu.com/ubuntu/ edgy main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://es.archive.ubuntu.com/ubuntu/ edgy-updates main restricted
deb-src http://es.archive.ubuntu.com/ubuntu/ edgy-updates main restricted

## Uncomment the following two lines to add software from the ‘universe’
## repository.
## 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
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb http://es.archive.ubuntu.com/ubuntu/ edgy universe
deb-src http://es.archive.ubuntu.com/ubuntu/ edgy universe

## 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://es.archive.ubuntu.com/ubuntu/ edgy-backports main restricted universe multiverse
deb-src http://es.archive.ubuntu.com/ubuntu/ edgy-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu edgy-security main restricted
deb-src http://security.ubuntu.com/ubuntu edgy-security main restricted
deb http://security.ubuntu.com/ubuntu edgy-security universe
deb-src http://security.ubuntu.com/ubuntu edgy-security universe

Bien, ahora vamos a actualizar la lista:

sudo apt-get update
sudo apt-get upgrade

Bien así ya tendremos nuestra lista de repositorios oficiales activada.