Upgraded to 14.04 from 12.04. Not sure if the upgrade was complete; laptop Dell Inspiron 3542 was powered down in spite of connected to power source. However, when the machine was started, login screen appeared.
Users' names were present. When the earlier password was keyed in, a message appeared above the password box as:
wrong password. Tried changing password thru root. No use. Noticed that Ctrl + Alt + F1 or Ctrl + Alt + T doesn't work - no change in the screen.
Would be thankful if a solution is provided here.