This question already has an answer here:
I've been using Ubuntu 13.10 for about a month now. I decided to give KDE a test run. Unfortunately, it installed the KDE login screen with it. I couldn't stand it, so I spent about half an hour trying to restore the original one.
Nothing worked, until I went in through Synaptic and removed most KDE packages installed. Bad idea. Now, when I boot the computer, I am greeted with a black screen. And by that, I mean the screen has turned off completely. I am able to navigate to a virtual terminal using CTRL+ALT+F1. Here's the interesting thing; When I go to TTY7, Plymouth is still running. I go to TTY8, and my screen turns off again.
Is there a way I can fix this and get the old login screen back, or is it time to start the preparations for a re-installation? Thanks!