проблема при обновлении [дубликат]

Failed to fetch cdrom://Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140417)/dists/trusty/main/binary-amd64/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

W: Failed to fetch cdrom://Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140417)/dists/trusty/restricted/binary-amd64/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/trusty/Release.gpg  Connection failed

E: Some index files failed to download. They have been ignored, or old ones used instead.