Well, I installed MDM, and found it's buggy with my VGA hardware due to the following screen after rebooting:
This screen repeats, even if I choose Yes or No
As I have access to the console (by pressing ALT+F2) I tried, sudo dpkg-reconfigure lightdm which gave me the following screen,
Even if I choose LightDM nothing happens at the next reboot. The first screen comes back!
dpkg -l | grep -i mdm command results me following,
ii mdm___________1.0.4-0~webupd8~precise_____Gnome Display Mnager
ii mint-mdm-themes__1.0.5-0~webupd8~precise1_____Linux Mint MDM Themes
(underscores are spaces)
Please help... I need LightDM login screen back!