may of found the problem,
harley@ZorinOS-Latitude-E6430:~$ sudo dpkg-reconfigure gdm
[sudo] password for harley:
dpkg-query: package 'gdm' is not installed and no information is available
Use dpkg --info (= dpkg-deb --info) to examine archive files.
/usr/sbin/dpkg-reconfigure: gdm is not installed
harley@ZorinOS-Latitude-E6430:~$ sudo dpkg-reconfigure lightdm
dpkg-query: package 'lightdm' is not installed and no information is available
Use dpkg --info (= dpkg-deb --info) to examine archive files.
/usr/sbin/dpkg-reconfigure: lightdm is not installed