problem with switching run levels

I normally have my Linux servers start in runlevel 3. Occasionally though, I
need to use the GUI (kde) on the console. What used to work to make the
switch was to type "startx" or "init 5". Now, when I issue those commands,
the console hangs trying to start processes and never boots into KDE.  

If I reboot the server, and edit inittab to automatically start in
runlevel5, KDE starts up with no problems.

I suspect a config file was modified along the way, but have been
unsuccessful tracking down the cause of this problem and fixing it.

Has anyone experienced a similar problem? Does anyone have any ideas on what
could be causing this and potential fixes?

Thanks
-dan