Utgivning är Ubuntu 12.04 LTS. Kan någon hjälpa mig? jag är nybörjare.

W:Failed to fetch cdrom://Ubuntu 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)/dists/precise/main/binary-i386/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 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)/dists/precise/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 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)/dists/precise/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 cdrom://Ubuntu 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)/dists/precise/restricted/binary-i386/Packages Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
, E:Some index files failed to download. They have been ignored, or old ones used instead.