Problema ao instalar e update

[Tat]

pessoal nao concigo instalar nada e nem fazer update alguem me pode ajudar
ERRO: ao instalar>>Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package update

alguem pode me enviar dados do seu:/etc/apt/sources.list



the security update on security.ubuntu.com couldn�t be acessed so those update
will note be made available to you this time. you should investigate this later.
commented out entries for security.ubuntu.com have have been added to the /etc/apt/sources.list

[lucianogf]

aqui uso kubuntu 7.10, os repositórios são os mesmos para o ubuntu da mesma versão

deb http://archive.ubuntu.com/ubuntu gutsy main
deb http://archive.ubuntu.com/ubuntu gutsy multiverse
deb http://archive.ubuntu.com/ubuntu gutsy restricted
deb http://archive.ubuntu.com/ubuntu gutsy universe
deb-src http://archive.ubuntu.com/ubuntu gutsy main
deb-src http://archive.ubuntu.com/ubuntu gutsy multiverse
deb-src http://archive.ubuntu.com/ubuntu gutsy restricted
deb-src http://archive.ubuntu.com/ubuntu gutsy universe
 
deb http://archive.ubuntu.com/ubuntu gutsy-backports main
deb http://archive.ubuntu.com/ubuntu gutsy-backports multiverse
deb http://archive.ubuntu.com/ubuntu gutsy-backports restricted
deb http://archive.ubuntu.com/ubuntu gutsy-backports universe
deb-src http://archive.ubuntu.com/ubuntu gutsy-backports main
deb-src http://archive.ubuntu.com/ubuntu gutsy-backports multiverse
deb-src http://archive.ubuntu.com/ubuntu gutsy-backports restricted
deb-src http://archive.ubuntu.com/ubuntu gutsy-backports universe
 
deb http://archive.ubuntu.com/ubuntu gutsy-proposed main
deb http://archive.ubuntu.com/ubuntu gutsy-proposed multiverse
deb http://archive.ubuntu.com/ubuntu gutsy-proposed restricted
deb http://archive.ubuntu.com/ubuntu gutsy-proposed universe
deb-src http://archive.ubuntu.com/ubuntu gutsy-proposed main
deb-src http://archive.ubuntu.com/ubuntu gutsy-proposed multiverse
deb-src http://archive.ubuntu.com/ubuntu gutsy-proposed restricted
deb-src http://archive.ubuntu.com/ubuntu gutsy-proposed universe
 
deb http://archive.ubuntu.com/ubuntu gutsy-updates main
deb http://archive.ubuntu.com/ubuntu gutsy-updates multiverse
deb http://archive.ubuntu.com/ubuntu gutsy-updates restricted
deb http://archive.ubuntu.com/ubuntu gutsy-updates universe
deb-src http://archive.ubuntu.com/ubuntu gutsy-updates main
deb-src http://archive.ubuntu.com/ubuntu gutsy-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu gutsy-updates restricted
deb-src http://archive.ubuntu.com/ubuntu gutsy-updates universe
 
deb http://archive.ubuntu.com/ubuntu gutsy-security main
deb http://archive.ubuntu.com/ubuntu gutsy-security multiverse
deb http://archive.ubuntu.com/ubuntu gutsy-security restricted
deb http://archive.ubuntu.com/ubuntu gutsy-security universe
deb-src http://archive.ubuntu.com/ubuntu gutsy-security main
deb-src http://archive.ubuntu.com/ubuntu gutsy-security multiverse
deb-src http://archive.ubuntu.com/ubuntu gutsy-security restricted
deb-src http://archive.ubuntu.com/ubuntu gutsy-security universe
 
deb http://security.ubuntu.com/ubuntu gutsy-security main
deb http://security.ubuntu.com/ubuntu gutsy-security multiverse
deb http://security.ubuntu.com/ubuntu gutsy-security restricted
deb http://security.ubuntu.com/ubuntu gutsy-security universe
deb-src http://security.ubuntu.com/ubuntu gutsy-security main
deb-src http://security.ubuntu.com/ubuntu gutsy-security multiverse
deb-src http://security.ubuntu.com/ubuntu gutsy-security restricted
deb-src http://security.ubuntu.com/ubuntu gutsy-security universe
 
deb http://espelhos.edugraf.ufsc.br/ubuntu gutsy-security main
deb http://espelhos.edugraf.ufsc.br/ubuntu gutsy-security multiverse
deb http://espelhos.edugraf.ufsc.br/ubuntu gutsy-security restricted
deb http://espelhos.edugraf.ufsc.br/ubuntu gutsy-security universe

[ICHUBrasil]

tenta assim

$sudo apt-get install update

ai depois tenta instalar os programas que você quer