Open notepad and put this in:
This will change the password of your victim and shutdown his computer after 60 seconds.
If by accident you click your bat file and cmd starts to run do this:
Go start > run > shutdown -a
This will stopthe computer from shutting down.
Another funny thing with cmd.
Open notepad and put :
Save your file as something.bat
Open notepad and put in :
This will pop up many pages and will CRASH your computer
Have fun, there's many others ways to have fun with cmd