How to set PATH environment variable?
- Select Computer from the Start menu
- Choose System Properties from the context menu
- Click Advanced system settings > Advanced tab
- Click on Environment Variables, under System Variables, find PATH, and click on it.
- In the Edit windows, modify PATH
- use
;(semicolon) for separating path entry texts
As you want shutdown.exe you want to have %SystemRoot%\System32 in your path.
If you want to restore the path variable to the default then here is the entire string:
%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\