Unable to install any softwares

Question

I just installed elementary on my HP Pavilion, dual boot with the pre-installed Windows 10. I can't install anything, using either the app center or apt-get. Here's what is happening when I try to install firefox

anthony@anthony-HP-Pavilion-Notebook:~$ sudo apt-get install firefox
[sudo] password for anthony: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package firefox 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 'firefox' has no installation candidate

And when I use the app-center, it simply does nothing. Thank you in advance for your help.

Answer 1

It's possible that you don't have the multiverse repository enabled that allows for installation of licensed software. Run sudo nano /etc/apt/sources.list and uncomment (remove #) from lines that don't match this:

## 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 xenial partner
# deb-src http://archive.canonical.com/ubuntu xenial partner

deb http://security.ubuntu.com/ubuntu xenial-security main restricted
# deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
# deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse

Hope this helps :).