sudo nano /etc/apt/sources.list
deb http://archive.ubuntu.com/ubuntu dapper main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu dapper main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu dapper-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu dapper-updates main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu dapper-security main restricted universe multiverse
deb-src http://security.ubuntu.com/ubuntu dapper-security main restricted universe multiverse