Nät jag kör drivrutinshanteraren står det "Misslyckades med att hämta förrådsinformation", och under "detaljer" står det:
W:The repository 'cdrom://Linux Mint 18.2 _Sonya_ - Release amd64 20170628 xenial Release' does not have a Release file., W

ata from such a repository can't be authenticated and is therefore potentially dangerous to use., W:See apt-secure(8) manpage for repository creation and user configuration details., W:GPG error:
http://repo.yandex.ru/yandex-browser/deb beta InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 218017D1CC5FDB34, W:The repository 'http://repo.yandex.ru/yandex-browser/deb beta InRelease' is not signed., W

ata from such a repository can't be authenticated and is therefore potentially dangerous to use., W:See apt-secure(8) manpage for repository creation and user configuration details., E:Failed to fetch cdrom://Linux Mint 18.2 _Sonya_ - Release amd64 20170628/dists/xenial/contrib/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, E:Some index files failed to download. They have been ignored, or old ones used instead.
Jag skrev in apt-cdrom i terminalen och fick det här meddelandet:
apt-cdrom
apt 1.2.24 (amd64)
Usage: apt-cdrom [options] command
apt-cdrom is used to add CDROM's, USB flashdrives and other removable
media types as package sources to APT. The mount point and device
information is taken from apt.conf(5), udev(7) and fstab(5).
Most used commands:
add - Add a CDROM
ident - Report the identity of a CDROM
See apt-cdrom(8) for more information about the available commands.
Configuration options and syntax is detailed in apt.conf(5).
Information about how to configure sources can be found in sources.list(5).
Package and version choices can be expressed via apt_preferences(5).
Security details are available in apt-secure(8).
Vad är fel, och vad ska jag göra?
Jag har installationsprogrammet på ett USB-minne. Vad ska jag då skriva för kommando?
apt-USB funkar inte.