I was running Mint 13 KDE 4.9 and everything was going fine. I was promoted that there were updates and proceeded to install them through the update manager. At some stage it asked me which display manager I would like to use and to be honest I'm not 100% sure which one I selected, I just thought "Cool, new display manager, where do I sign?" Anyway I went with the one that the upgrade wanted to use or something to that effect. I think it was KDM.
Thereafter I my login manager changed somehow and I now have to type my username in every time. Upon logging in the screen flashes black for a second and the cursor becomes a white X then back to normal. Now when I watch videos the desktop crashes, everything runs except there are no panels and the desktop is black.
I have since tried changing to lightdm which didn't help have have done dist-upgrade and have currently got KDE 4.9.1. I get a crash report every time I switch my computer on and although sometimes the desktop revives itself, the majority of the time I am stuck using ALT-F2 to get stuff done. Not cool...
What can I do (bearing in mind I'm a noob)?


