the problem was solved as follows
ny trial and error method.
anyway iwas ready to reinstall 5th time
so i moved the /root /mnt and created new /root
deleted the ramaswamy home directory
deletd the user ramaswamy
added another user
noe i find that all 2 new users and root can login to kde.
the xauth and .kde get corrupted or some illegal operation saving must be spoiling the files in home folders.
i was able to reproduce the same faults and remedies .
only we have to be prepared to delete the respedtive home folders at any time.
so keep all data in different folder in /home.
so if something happens like this data wont be lost.
mind that all these troubles was with kde login only.
console login was ok for root and user.
use yast to add remove user.
may be this helps someone