@NucleusKore
Thank you Sir, Thanks a lot for your nice help....as I know you are dedicated Suse user.
Yes my problem solve with GUI way which you described.
@tech_your_future
Where is the KDE Control Center ?
I found Configure Desktop/Personal Settings, where System Administration--->Login Manger--->(After enabling Administrator Mode)--->Convenience
It display the Auto Login Disabled.
here is the screenshot
What I do now ?
I want every time it ask me for user name and password and also give me the option like choosing desktop environment.....like a proper linux behaviour.