W:GPG error: http://ppa.launchpad.net trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C777F0E392FAE28B, W:GPG error: https://download.01.org vivid InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A902DDA375E52366, W:Size of file /var/lib/apt/lists/partial/download.01.org_gfx_ubuntu_15.04_main_dists_vivid_main_binary-amd64_Packages.gz is not what the server reported 11400 1592, W:GPG error: http://ppa.launchpad.net vivid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C777F0E392FAE28B, W:Failed to fetch http://ppa.launchpad.net/gstreamer-developers/ppa/ubuntu/dists/vivid/main/binary-amd64/Packages  404  Not Found
, W:Failed to fetch http://ppa.launchpad.net/gstreamer-developers/ppa/ubuntu/dists/vivid/main/binary-i386/Packages  404  Not Found
, W:Failed to fetch http://ppa.launchpad.net/gwibber-daily/ppa/ubuntu/dists/vivid/main/binary-amd64/Packages  404  Not Found
, W:Failed to fetch http://ppa.launchpad.net/gwibber-daily/ppa/ubuntu/dists/vivid/main/binary-i386/Packages  404  Not Found
, W:Failed to fetch http://ppa.launchpad.net/michael-astrapi/ppa/ubuntu/dists/vivid/main/binary-amd64/Packages  404  Not Found
, W:Failed to fetch http://ppa.launchpad.net/michael-astrapi/ppa/ubuntu/dists/vivid/main/binary-i386/Packages  404  Not Found
, E:Some index files failed to download. They have been ignored, or old ones used instead.