How To Automatically Shut Down Your Computer Without Using Third Party Softwares

• Open   Control Panel window click on System and Security  then  Click on Schedule Tasks under Administrative Tools at the bottom.
• In the Actions  menu click Create Basic Task.
• Type some name and details and click Next.
• Select the option you want (daily, weekly, etc.)
• Select the date and time you want to shutdown your PC. 
• Select Start a Program then click Next.
• To select the program or script browse to C:\Windows\System32\shutdown.exe and click Next.
• Then click Finish .
• In the center portion  of the window you can select your task and click Run on the bottom right of the window.
• Have fun.