Easiest way to fix the problem is to use YaST. Select System and then select /etc/sysconfig Editor. In the left hand navigation tree, select Desktop and then DISPLAYMANAGER. Set this to "kdm". Mine had been set to "xdm". Set the DISPLAYMANAGER_KDM_THEME to "SuSE"
You will also want to go to the Window manager and make sure that DEFAULT_WM is set to "kde".
One more item that I had to change was under Display Manager. I had to set KDM_SHUTDOWN to "all". This restored the options to reboot or halt the system in the Log out menu.
Merton Campbell Crockett
Ditto on the problem here. Brand new install of 9.3 - all things were OK until (presumably) I installed the nvidia drivers... Now I get XDM, no shutdown, and a popup on the KDE screen saying the nvidia driver module taints the kernel. Arg.