Possible Duplicate:
How can you remove Unity?
How to fully remove Unity Desktop Environment and associated files and dependencies from Ubuntu 12.04 and have a pure KDE installation ?
Possible Duplicate:
How can you remove Unity?
How to fully remove Unity Desktop Environment and associated files and dependencies from Ubuntu 12.04 and have a pure KDE installation ?
From the terminal:
sudo apt-get remove unity*
and thensudo apt-get autoremove
so nothing stays, then proceed to Install KDEsudo apt-get install kubuntu-desktop
.