I just upgraded Kubuntu with an iso, trying to install Steam i get this:
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. steam:i386 : Depends: > libgl1-mesa-glx:i386 but it is not going to be installed > Recommends: nvidia-driver-libs-i386:i386 but it is not installable E: Unable to correct problems, you have held broken > packages.
I had newer Mesa drivers from Paulo's PPA, i uninstalled 'em and removed the PPA, then reinstalled Mesa. I tried this: How do I resolve unmet dependencies after adding a PPA?