I've tried installing through
sudo apt-get install and software center for both Synaptic and Grace (a plotting tool). For
sudo apt-get install, I get
E: Package 'synaptic' has no installation candidate
and for the software center I'm getting:
there isn't a software package called "grace" in youc current software sources
I have "main", "universe", "restricted", and "multiverse" checked for software sources. I'm an ubuntu noob. Thanks!