Hello,


I'm having an issue installing Steam on Ubuntu MATE 16.04 LTS and can't post the message on the AskUbuntu site becayse I apparenlty don't have enough reputation points [apparently the error message i get has 2 weblinks in it so i cant post it].

Can someone please help me with this? Here is the error message I keep getting


W:Target Sources (main/source/Sources) is configured multiple times in /etc/apt/sources.list.d/noobslab-ubuntu-themes-xenial.list:2 and /etc/apt/sources.list.d/noobslab-ubuntu-themes-xenial.list:3, W:Target Sources (main/source/Sources) is configured multiple times in /etc/apt/sources.list.d/ravefinity-project-ubuntu-ppa-xenial.list:2 and /etc/apt/sources.list.d/ravefinity-project-ubuntu-ppa-xenial.list:3, W:Target Sources (main/source/Sources) is configured multiple times in /etc/apt/sources.list.d/ravefinity-project-ubuntu-ppa-xenial.list:2 and /etc/apt/sources.list.d/ravefinity-project-ubuntu-ppa-xenial.list:4, W:The repository 'cdrom://Ubuntu-MATE 16.04.2 LTS _Xenial Xerus_ - Release amd64 (20170215) xenial Release' does not have a Release file., W:Data 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: https://download.opensuse.org/reposit.../xUbuntu_16.04 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A7D1D38BEB6D886, W:The repository 'https://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_16.04 Release' is not signed., W:Data 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:https://content.runescape.com/downlo...sty/InRelease: Signature by key AAC9264309E4D717441DB9527373B12CE03BEB4B uses weak digest algorithm (SHA1), E:Failed to fetch cdrom://Ubuntu-MATE 16.04.2 LTS _Xenial Xerus_ - Release amd64 (20170215)/dists/xenial/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, E:Some index files failed to download. They have been ignored, or old ones used instead.