Why users are not able to login into the GUI mode?

Issue

• Cannot login to console as any user.
• Why the system does not boot into a Gui mode?
• Why the system user cannot login into GUI mode?

• The followings are reported on /var/log/messages. What does it mean?

  Jun 18 10:52:54 hostname init: vmware-tools pre-start process (5769) terminated with status 1
  Jun 18 10:52:54 hostname init: prefdm main process (5980) terminated with status 1
  Jun 18 10:52:54 hostname init: prefdm main process ended, respawning