synaptic/update manager update in ubuntu 10.04

Even if I’m trying to update with update manager or apt, synaptic is not updating. I faced this weired problem in ubuntu 10.04.
There is a very simple solution to get rid out of this problem.
Just execute this command in your terminal.

sudo gedit /etc/apt/sources.list

remove the line which contains CD/DVD ROM and the next line (if any, without starting with #)

update again with

sudo apt-get update

If you are no too unlucky you are already done with updating. enjoy 😀