Stop KDM ( /etc/init.d/kdm stop )

Try starting X from the command line (no display manager) with startx or
just X. Can you do this as root? Does startx work as a normal user? 

If the above works, we get to poke at KDM configs. If it doesn't work, X
isn't configured properly. (You ran dexter right?)

I'm going to make a guess that KDM is calling X and telling it to use
/etc/X11/XF86Config, when it should be using /etc/X11/XF86Config-4

Check /etc/X11/kdm/Xservers. 
/etc/X11/X -xf86config /etc/X11/XF86Config-4 should start the X server.
(/etc/X11/X is a sym link to /usr/bin/X11/XFree86)

Hope that helps a little...

--
Andy Zbikowski, Sys Admin   | (WEB) http://www.ltiflex.com
LTI Flexible Products, Inc. | (PH)  763-428-9119 (EX) 132
21801 Industrial Blvd       | (FX)  763-428-9126
Rogers, MN  55374           | (PCS) 612-306-6055