Possible Duplicate:
Failed to download repository information due to missing CDROM
I have been using Ubuntu for about 6 months now without any problems until I ran the update manager yesterday and kept getting this message:
Failed to download repository information Check your Internet connection
Then in the more details box it reported:
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/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.
I have tried using the terminal commands given but have had no luck.