Kali directly boot into emergency mode. then i cant i can't get into graphical mode

I have recently faced a problem with my kali linux, The problem is that i can't get into graphical mode, When ever i reboot my kali its starts in "welcome to emergency mode" then it ask me the root password . i just reboot the system sevaral time but still the issue is not resolved . ineed to boot system in graphical mode insted of emergency mode :(

kali version : kali 2.0
hardware :lenovog480 dualcore 2gb ram
Activity i done last day: use reaver , edit /etc/fstab

Hi,

while in emergency mode, just undo what you did in /etc/fstab then reboot by typing "systemctl reboot"

have a nice day.