I have tried few tutorials from Ask-Ubuntu and Ubuntu forums to remove kde completely from ubuntu 13.10 which didn’t worked for me, and i finally found the solution myself.
follow this tutorial to remove KDE desktop ,KDE applications and KDE login window from Ubuntu .
Run this command in terminal to remove KDE and all bundled applications
sudo apt-get remove kde-desktop kde-baseapps-data kde-runtime-data kde-base-artwork kde-style-oxygen kdegames-data kde-wallpapers-default kdelibs5-data kde-window-manager kdelibs5-plugins kde-window-manager-common kdelibs-bin kde-workspace kdepasswd kde-workspace-bin kdepimlibs-kio-plugins kde-workspace-data kdepim-runtime kde-workspace-kgreet-plugins kde-runtime kde-zeroconf
Restore Ubuntu unity login window (LightDM theme/greeter)
To restore the ubuntu login window we need to edit LightDM configuration file located in ‘/etc/lightdm/lightdm.conf ‘.
Run this command in terminal to open the LightDM configuration file in gedit text editor .
gksudo gedit /etc/lightdm/lightdm.conf
Now remove all kde entries and add this line