sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup
sudo gedit /etc/apt/sources.list

用以下內容替換文件中的所有內容
deb http://Ubuntu.cn99.com/ubuntu/ dapper main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ dapper-updates main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ dapper-security main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ dapper-backports main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu-cn/ dapper main restricted universe multiverse

sudo apt-get update

sudo apt-get install w32codecs