#dpkg-reconfigure xserver-xorg
xserver-xorg postinst warning: not updating /etc/X11/X; no default X server
   configured; run "dpkg-reconfigure xserver-xorg" to correct this
md5sum: /etc/X11/xorg.conf: No such file or directory
dexconf: error: cannot generate configuration file; shared/default-x-server not 
set.  Aborting.  Reconfigure the X server with "dpkg-reconfigure" to correct 
this problem.
xserver-xorg postinst warning: error while preparing new Xorg X server
   configuration file in /etc/X11/xorg.conf.dpkg-new; not attempting to
   update existing configuration