софт-центр потерпел крах; не будет переустановлен после попытки исправить

Я в тупике.

В моей системе софт-центр зависал в течение 2 секунд после запуска. Я попытался решить проблему, запустив:

sudo apt-get remove --purge software-center
sudo apt-get install software-center

К сожалению, установка не удалась. Я получаю эту ошибку:

sudo apt-get install software-centerReading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 software-center : Depends: python-gi (>= 3.4.0-1ubuntu0.1) but it is not going to be installed
                   Depends: python-gi-cairo but it is not going to be installed
                   Depends: python-aptdaemon (>= 0.40) but it is not going to be installed
                   Depends: python-aptdaemon.gtk3widgets but it is not going to be installed
                   Depends: oneconf (>= 0.2.6) but it is not going to be installed
                   Depends: python-oneconf (>= 0.3) but it is not going to be installed or
                            oneconf (< 0.3) but it is not going to be installed
                   Recommends: sessioninstaller but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

В отчаянии я попробовал apt-get build-deps, но это также не удалось.

sudo apt-get build-dep python-gi python-gi-cairo python-aptdaemon.gtk3widgets oneconf python-oneconf oneconf sessioninstaller
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Picking 'pygobject' as source package instead of 'python-gi'
The following packages have unmet dependencies:
 libcairo2-dev : Depends: libfontconfig1-dev (>= 2.2.95) but it is not going to be installed
 libglib2.0-dev : Depends: libglib2.0-0 (= 2.36.0-1ubuntu2) but 2.36.3-0ubuntu1~raring1 is to be installed
                  Depends: libglib2.0-bin (= 2.36.0-1ubuntu2)
E: Build-dependencies for python-gi could not be satisfied.

Есть идеи?