If Node.js is installed on your computer but the command prompt is still showing the error, this can be caused due to Node.js not being recognized by the system.

I hope this guide helped you to fix the issue. Read: Java is not recognized as internal or external command How to install npm in cmd?

One of the computers here is giving this message when trying to ftp at the command line. It's running a fresh install of Windows NT4 sp6a. I've checked and the path in environmental variables is ...

If Java is not recognized as internal or external command, you need to make sure that the installation is not problematic and its path is recognized as system variables.