Somehow I managed to do a fresh install of SuSe 8.1 in a way that I have a simple login window (just username and password there) without any option to select display managers to be started.

I want to be able to choose between display managers; so is it possible to add such an option now, when the installation has been completed?

I already tried everything I could; I hunted down the runlevel editor, the sysconfig editor, the kde control center (session manager tab), and yast2 with no use.
It only made me confused, not knowing what login manager I actually have now:
- according to the "runlevel editor", runlevel 5 is a system with network and xdm
- according to the kde control center I have kdm (but no changes I make there take any effect on the login window, besides I have no /opt/kde3/share/apps/kdm directory; and all icons that should be on the session manager tab are missing)
- yast2 says I have xdm (I suspect yast2 may be right, but I found no way to change to kdm there; besides it advises to use kde control center for that)

Maybe I ommitted to install something that is needed to use kdm as a login manager?
I only found one rpm that has "kdm" in the package name, but that is something for Netscape plugins...

Could you help me how to install and/or activate kdm in SuSe 8.1; and thus recover my good old login window?