Ошибка Unable to locate package <имя пакета>

[ubuntu beginner]

При попытке загрузить пакет (любой!) с apt-get  появляется следующий текст:
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package gparted
E: Unable to locate package ntfsprogs

apt-get update и apt-get upgrade делала, не помогает. Содержание sources.list:
# deb cdrom:[Ubuntu 17.04 _Zesty Zapus_ - Release i386 (20170412)]/ zesty main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://ru.archive.ubuntu.com/ubuntu/ zesty main universe restricted
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://ru.archive.ubuntu.com/ubuntu/ zesty-updates main universe restricted
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty-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://ru.archive.ubuntu.com/ubuntu/ zesty universe
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty universe
deb http://ru.archive.ubuntu.com/ubuntu/ zesty-updates universe
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty-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://ru.archive.ubuntu.com/ubuntu/ zesty multiverse
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty multiverse
deb http://ru.archive.ubuntu.com/ubuntu/ zesty-updates multiverse
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty-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://ru.archive.ubuntu.com/ubuntu/ zesty-backports main restricted universe multiverse
# deb-src http://ru.archive.ubuntu.com/ubuntu/ zesty-backports main restricted universe multiverse

Использую Ubuntu 17.04 Desktop. Что же мне делать с этим apt-get?

[БТР]

17.04 Zesty Zapus больше не поддерживается. Пользуйтесь LTS-версиями.

[ubuntu beginner]

Оу...не знала, спасибо