Обновление программного обеспечения Xubuntu не работает?

При запуске обновления программного обеспечения я получил сообщение о том, что либо мои сетевые подключения больше не работают, либо хранилища больше не доступны. Я уже попытался перезагрузить компьютер и запустить программу обновления программного обеспечения с панели настроек. Я бегу Xubuntu 13.04. Программное обеспечение Uupdate работало в прошлом.

sudo apt-get update дает мне следующий вывод: (Мне пришлось убрать большой кусок ссылок, потому что мне не разрешено публиковать более 2 ссылок)

Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring Release.gpg
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring Release
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/main 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/multiverse 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/restricted 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/universe 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/main 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/multiverse 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/restricted 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
Err cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/universe 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
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/main Translation-en_US
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/main Translation-en
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/multiverse Translation-en_US
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/multiverse Translation-en
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/restricted Translation-en_US
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/restricted Translation-en
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/universe Translation-en_US
Ign cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1) raring/universe Translation-en
----------------------------------------------------------------------------
Fetched 950 kB in 10s (88.0 kB/s)                                              
W: GPG error: http://download.opensuse.org  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 977C43A8BA684223
W: Failed to fetch cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/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://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/multiverse/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://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/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://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/universe/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://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/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://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/multiverse/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://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/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

W: Failed to fetch cdrom://Xubuntu 13.04 _Raring Ringtail_ - Release amd64 (20130423.1)/dists/raring/universe/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.