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 then sudo apt-get autoremove so nothing stays, then proceed to Install KDE sudo apt-get install kubuntu-desktop.