If this issue somehow is not fixed, you can always shut down your computer by hitting CTRL+ALT+DEL(Delete) on your keyboard and a screen should come up That says: Lock, Switch User, Sign Out, Change a Password, Task Manager , and cancel. Don't click any of those, go to the bottom right corner and there should be a power button there next to a 3/4th circle, like this picture. Just click that and you should be able to shut down.