패키지에 설치 후보가 없습니다.

나는 Ubuntu 15.04를 가지고 있으며 무언가를 다운로드하려고 할 때마다(sudo apt-get install을 사용하여) 다음과 같이 말합니다.

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package <packagename> is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package '<packagename>' has no installation candidate

"sudo apt-get update"를 시도했는데 끝에 다음과 같이 표시됩니다.

W: Failed to fetch http://ppa.launchpad.net/irie/blender/ubuntu/dists/vivid/main/binary-amd64/Packages  404  Not Found

W: Failed to fetch http://ppa.launchpad.net/irie/blender/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.

또한 "소프트웨어 및 업데이트" 창의 "우분투 소프트웨어" 탭에 있는 모든 확인란이 선택되어 있는지 확인하고 "sudo apt-get 업그레이드"를 시도했지만 아무 것도 작동하지 않았습니다.

또한 내 source.list 파일은 다음과 같습니다. 괜찮아 보입니다.

# deb cdrom:[Ubuntu 15.04 _Vivid Vervet_ - Release amd64 (20150422)]/ vivid main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://old-releases.ubuntu.com/ubuntu vivid main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://old-releases.ubuntu.com/ubuntu vivid-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://old-releases.ubuntu.com/ubuntu vivid universe
deb http://old-releases.ubuntu.com/ubuntu vivid-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://old-releases.ubuntu.com/ubuntu vivid multiverse
deb http://old-releases.ubuntu.com/ubuntu vivid-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://old-releases.ubuntu.com/ubuntu vivid-backports main restricted universe multiverse

deb http://old-releases.ubuntu.com/ubuntu vivid-security main restricted
deb http://old-releases.ubuntu.com/ubuntu vivid-security universe
deb http://old-releases.ubuntu.com/ubuntu vivid-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu vivid partner
# deb-src http://archive.canonical.com/ubuntu vivid partner
deb http://www.openprinting.org/download/printdriver/debian/ lsb3.2 contrib

또한 이와 유사한 다른 질문이 있다는 것을 알고 있지만 어떤 솔루션도 나에게 도움이 되지 않았습니다.

편집하다:

내가 볼 수 있듯이 댓글에 있는 많은 사람들은 내가 오래된 버전의 Ubuntu를 사용하고 있기 때문에 source.list의 "archives.ubuntu.com" 줄을 "old-releases.ubuntu.com"으로 변경하라고 제안했습니다. 나는 이것을 시도했고 "sudo apt-get update"(일부 인덱스 파일을 다운로드하지 못함)를 입력하면 동일한 메시지가 나타나고 패키지를 설치하려고 할 때 동일한 일이 발생합니다.

댓글의 일부 다른 사람들은 최신 Ubuntu 버전으로 업그레이드할 것을 제안했으며, 이를 시도해 보았지만(sudo do-release-upgrade) 결국 다음과 같이 말했습니다.

Cannot upgrade, an upgrade from 'vivid' to 'xenial' is not supported with this tool.

또한 sudo do-release update -d를 사용하여 업그레이드를 시도했지만 다음과 같이 말했습니다.

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