abaixo é a saída do comando "sudo apt-get update"
ayush@cayush:~$ sudo apt-get update
[sudo] password for ayush:
Ign http://archive.ubuntu.com wily InRelease
Ign http://archive.ubuntu.com wily-updates InRelease
Ign http://archive.ubuntu.com wily-backports InRelease
Ign http://archive.ubuntu.com wily-security InRelease
Ign http://archive.ubuntu.com wily Release.gpg
Ign http://archive.ubuntu.com wily-updates Release.gpg
Ign http://archive.ubuntu.com wily-backports Release.gpg
Ign http://archive.ubuntu.com wily-security Release.gpg
Ign http://archive.ubuntu.com wily Release
Ign http://archive.ubuntu.com wily-updates Release
Ign http://archive.ubuntu.com wily-backports Release
Ign http://archive.ubuntu.com wily-security Release
Err http://archive.ubuntu.com wily/main Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/restricted Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/universe Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/multiverse Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/main amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/restricted amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/universe amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/multiverse amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/main i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/restricted i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/universe i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily/multiverse i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Ign http://archive.ubuntu.com wily/main Translation-en_IN
Ign http://archive.ubuntu.com wily/main Translation-en
Ign http://archive.ubuntu.com wily/multiverse Translation-en_IN
Ign http://archive.ubuntu.com wily/multiverse Translation-en
Ign http://archive.ubuntu.com wily/restricted Translation-en_IN
Ign http://archive.ubuntu.com wily/restricted Translation-en
Ign http://archive.ubuntu.com wily/universe Translation-en_IN
Ign http://archive.ubuntu.com wily/universe Translation-en
Err http://archive.ubuntu.com wily-updates/main Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/restricted Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/universe Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/multiverse Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/main amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/restricted amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/universe amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/multiverse amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/main i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/restricted i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/universe i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-updates/multiverse i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Ign http://archive.ubuntu.com wily-updates/main Translation-en_IN
Ign http://archive.ubuntu.com wily-updates/main Translation-en
Ign http://archive.ubuntu.com wily-updates/multiverse Translation-en_IN
Ign http://archive.ubuntu.com wily-updates/multiverse Translation-en
Ign http://archive.ubuntu.com wily-updates/restricted Translation-en_IN
Ign http://archive.ubuntu.com wily-updates/restricted Translation-en
Ign http://archive.ubuntu.com wily-updates/universe Translation-en_IN
Ign http://archive.ubuntu.com wily-updates/universe Translation-en
Err http://archive.ubuntu.com wily-backports/main Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/restricted Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/universe Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/multiverse Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/main amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/restricted amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/universe amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/multiverse amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/main i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/restricted i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/universe i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-backports/multiverse i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Ign http://archive.ubuntu.com wily-backports/main Translation-en_IN
Ign http://archive.ubuntu.com wily-backports/main Translation-en
Ign http://archive.ubuntu.com wily-backports/multiverse Translation-en_IN
Ign http://archive.ubuntu.com wily-backports/multiverse Translation-en
Ign http://archive.ubuntu.com wily-backports/restricted Translation-en_IN
Ign http://archive.ubuntu.com wily-backports/restricted Translation-en
Ign http://archive.ubuntu.com wily-backports/universe Translation-en_IN
Ign http://archive.ubuntu.com wily-backports/universe Translation-en
Err http://archive.ubuntu.com wily-security/main Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/restricted Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/universe Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/multiverse Sources
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/main amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/restricted amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/universe amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/multiverse amd64 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/main i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/restricted i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/universe i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Err http://archive.ubuntu.com wily-security/multiverse i386 Packages
404 Not Found [IP: 91.189.88.162 80]
Ign http://archive.ubuntu.com wily-security/main Translation-en_IN
Ign http://archive.ubuntu.com wily-security/main Translation-en
Ign http://archive.ubuntu.com wily-security/multiverse Translation-en_IN
Ign http://archive.ubuntu.com wily-security/multiverse Translation-en
Ign http://archive.ubuntu.com wily-security/restricted Translation-en_IN
Ign http://archive.ubuntu.com wily-security/restricted Translation-en
Ign http://archive.ubuntu.com wily-security/universe Translation-en_IN
Ign http://archive.ubuntu.com wily-security/universe Translation-en
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/main /source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/restricted/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/universe/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/multiverse/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/main/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/restricted/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/universe/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/multiverse/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/main/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/restricted/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/universe/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily/multiverse/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/main/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/restricted/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/universe/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/multiverse/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/main/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/restricted/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/universe/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/multiverse/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/main/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/restricted/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/universe/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-updates/multiverse/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/main/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/restricted/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/universe/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/multiverse/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/main/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/restricted/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/universe/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/multiverse/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/main/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/restricted/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/universe/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-backports/multiverse/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/main/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/restricted/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/universe/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/multiverse/source/Sources 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/main/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/restricted/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security /universe/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/multiverse/binary-amd64/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/main/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/restricted/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/universe/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/wily-security/multiverse/binary-i386/Packages 404 Not Found [IP: 91.189.88.162 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.
Eu pesquisei sobre esse problema e encontrei alguns relacionados, mas nenhuma dessas soluções funcionou no meu caso.
Nota: - Estou usando o Ubuntu versão 15.10.
Por favor ajude. Eu sou novo no linux.