sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup
sudo gedit /etc/apt/sources.list
用以下内容替换文件中的所有内容
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