Media change: please insert the disc labeled‘Debian GNU/Linux 7.9.0 _Wheezy_ - Official amd64 CD Binary-1’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.