root@localhost:~# apt-get install software-center
Reading 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-gobject (>= 3.0) but it is not going to be installed
Depends: python-gobject-cairo
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
Recommends: gir1.2-launchpad-integration-3.0 but it is not installable
Recommends: sessioninstaller but it is not installable
E: Unable to correct problems, you have held broken packages.
O que eu acredito que você tenha quebrado pacote pode ser, enquanto sua tentativa anterior para instalar o centro de software, eu sugiro que você verifique o seguinte ..
sudo apt-get purge software-center
tente
sudo apt-get update
sudo apt-get install python-gobject-cairo python-aptdaemon.gtk3widgets sessioninstaller -y
Como último passo
sudo apt-get install software-center