You need to download PsShutDown
then run it. It has to be placed either in the current directory when you open a Command Prompt or in a directory defined in the PATH environment variable.
If you downloaded PSTools
then it is included in that package. The PsTools
download package includes an HTML help file with complete usage information for all the tools.
You need to either add the directory (Folder) you unzipped PSTools in to your PATH statement or copy psshutdown.exe to the directory you want to run it form. Normally this would be C:\Users\xxxxxxxx, where xxxxxxxx is your account name.
The when you run psshutdown, you will no longer get a command not recognized error message.
Hope that helps.