Here is for reference: http://old-releases.ubuntu.com/releases/
It contains repositories and distributions for all old versions of Ubuntu, Kubuntu and Edubuntu.
Still for reference, "sources.list" in /etc/apt should have lines like :
deb http://old-releases.ubuntu.com/ubuntu/ edgy main restricted
deb-src http://old-releases.ubuntu.com/ubuntu/ edgy main restricted
deb http://old-releases.ubuntu.com/ubuntu/ edgy-updates main restricted
deb-src http://old-releases.ubuntu.com/ubuntu/ edgy-updates main restricted
deb http://old-releases.ubuntu.com/ubuntu/ edgy universe
deb-src http://old-releases.ubuntu.com/ubuntu/ edgy universe
deb http://old-releases.ubuntu.com/ubuntu/ edgy-backports main restricted universe
deb-src http://old-releases.ubuntu.com/ubuntu/ edgy-backports main restricted universe
deb http://old-releases.ubuntu.com/ubuntu edgy-security main restricted
deb-src http://old-releases.ubuntu.com/ubuntu edgy-security main restricted