A batch file to minimize other applications

Try:

start /min "" firefox

.. or (if FireFox is your default browser):

start /min "" "http://google.com"

windows firefox vbscript batch-file

Have you tried:
start /min C:\Program Files\Mozilla Firefox\firefox.exe

using the forward slash?

windows firefox vbscript batch-file

The proper parameter would be -turbo, but it is long obsolete and probably not functional.

start "path\firefox.exe http://example.com/file.html" /MIN

might work better.

EDIT: Oops, it has already been suggested.

CodeHunter