use shell.run
to execute the video(the following codes are JScript):
shell = new ActiveXObject("WScript.shell") ;
shell.run('"C:\\path\\to\\video.mp4"');
...what will open the video with the default-player
to open it with VLC use:
shell.run('"C:\\path\\to\vlc.exe" "C:\\path\\to\\video.mp4"');