Help --Screwed Xstartup file

Hello SuSE folkz, Friend of mine a typical MS winblows guy out of curiosity accidentally deleted /etc/X11/xdm/Xstartup file on my Linux box. Now I can't login into Linux box with graphical KDM login nor turn off Xserver to correct this issue in command prompt. Could somebody please advise me how to turn off xdm to login into box over the command prompt. I'm afraid that I will need to reinstall the whole box. Thanks in advance. Alex -- MS Windows users should be covered under the Americans with Disabilities Act.