I thank you so much for your advice!
I am a novice to Linux so I was very happy to learn how to go into run level 1.
I logged in as root successfully and did the following actions:
chmod 0644 /etc/passwd
chmod 0400 /etc/shadow
I also went into /opt/kde3/share/config/kdeglobals and added to the end of the file:
But unfortunately I still have the same problem- nothing has changed.
I appreciate any further suggestions or advice
Once again, thank you for your kind support, as this gives me a great opportunity for learning Linux!