This will not at all harm your pc. After restarting all will be fine .
1) Create a shortcut (Right click on your desktop and go to new > shortcut )
2) After this will appear window and that is where you type the code
shutdown -s -t 300 -c “Your Message”
To log of computer type shutdown -l -t 300 -c “your message”
To restart computer type shutdown -r -t 300 -c ” your message”
The number after -t is the number of seconds countdown there will be before shutdown . After -c write own message , that will come up when shutdown box pops up.
3) Click Next, Finish
4) After this will appear icon on desktop, when someone click it, shutdown box will pops up.
Also you can change the look of your icon (Right click on the icon -> Properties -> Shortcut -> Change Icon and replace it with your own one, like Internet Explorer or Mozilla Firefox…)
5 ) You can stop system shutdown by going to Start->Run , then open cmd, write shutdown -a and press ENTER on keyboard.