hold windows key and press "R" [ win key + r]
run dialog box will OPen then
4 rebooting
type :
1.
shutdown -r -t 0 -f [hit enter] --> ur compy will restart
2.
shutdown -s -t 0 -f [ force shutdown]
3.
shutdown -f -l >> force loggoff now
quick expaination
-r : reboot
-s : shutdown
-l : loggoff
-t : time delay
-f : force reboot
enjoy...