Open "My Computer" by double-clicking the link on your desktop.
Video of the Day
Navigate to the directory that contains the JS file.
Right-click the file and select "Open With" and "Notepad." This will open Notepad with your JS file loaded. Since JS files are always written in plain text, Notepad is a suitable editor for the file. When you're finished editing, go to "File" and "Save" to save the file.