First, at the command line as root, do 'urpmi XFree86'
This should help you reinstall the X-windows system
Second, at the command line as root, try 'XFdrake' to reconfigure X-windows
If all else fails, try removing XFree86 using rpm, then run the Mandrake CD, selectiong the upgrade option to 'upgrade' Mandrake 9.2 to mandrake 9.2
When the installer gets to the screen with all the configuration options, you should be able to use the option to set up X-windows there