Problem installing packages and apps

[LinuxUser666]

Hello fellow Ubuntu users, I am using Ubuntu 12.04 with GNOME DE. I seem to have a problem lately...you see whenever I try to use an apt to download and install something, for instance alien with:

sudo apt-get install alien

and get result like this:

Media change: please insert the disc labeled 'Ubuntu 12.04.1 LTS _Precise Pangolin_ - Release i386 (20120817.3)'
in the drive '/cdrom/' and press enter

I do that, put the CD in the drive but nothing is happening. Can someone please explain what is it all about and how to fix it?

Thank you, stay brutal.

[CatKiller]

If you have an Internet connection, you don't want to use the cd as a repository. Disable it in Software Sources, or remove that line from sources.list.

[LinuxUser666]

Ok I did that, removed my cd from repository lists and I am all clear now.

Thanks for the tip, stay brutal, my regards.