Remove CD-ROM from apt-get repositories Debian 7

I noticed that Debian 7 uses the media in the CD-ROM when using the “apt-get” utility.
The following message comes up when attempting to install or update a program using apt-get:

Media change: please insert the disc labeled
‘Debian GNU/Linux 6.0.0 _Squeeze_ – Official i386 DVD Binary-1 20110205-17:27′
in the drive ‘/media/cdrom/’ and press enter

The fix is easy. We need to remove the CD-ROM as a source for apt-get.
To do this, edit the following file: /etc/apt/sources.list

Comment or delete the line for the CD-ROM, save the changes, and try apt-get again.
This time, it should use the online repositories.