No use the Windows task scheduler that will allow you to shut down your computer after 12 hours not that there's any reason to shut it down after 12 hours but sure why not
Windows task scheduler works awesome just google it for the exact instructions of setting it i have mine set to shut my pc down at 2am everyday because i dont like to leave the bot running all night.
- open the start menu
- Klick on "Run" (without "")
- type in "cmd" (without "")
- in the command promt type in "shutdown /s /f /t [time in seconds]"
- for 12h: shutdown /s /f /t 43200
- you can close the command prompt