I wanted to try out some different desktop environment other than Unity so I installed kubuntu-desktop using
sudo apt-get install kubuntu-desktop
then I didn't like it so much, so I removed it according to an answer to one of the questions here by executing
sudo apt-get purge kubuntu-desktop
sudo apt-get autoremove
but apparently this did not completely remove it as I still noticed that I could still choose KDE Plasma from my login screen, some programs that were installed with this desktop environment are still installed, I still have my start up and shutdown screens in black and say kubuntu, etc.
I tried to re-install ubuntu-desktop using
sudo apt-get install --reinstall ubuntu-desktop
in a try to get my start up/shutdown screens back to be consistent with the currently installed desktop environment at the time (i.e., ubuntu-desktop), but this wasn't successful.
I then installed xubuntu-desktop using
sudo apt-get install xubuntu-desktop
and now I'm still having my start up/shutdown kubuntu black screens in addition to xubuntu login screen and I didn't see an option in the xubuntu login screen to get back to Unity if I wanted to though.
My questions now is, in this situation, how to completely remove kubuntu-desktop and everything that is related and keep ubuntu-desktop and xubuntu-desktop installed?
Thank you!