I need to use Java 1.6.0_20 for the software I'm running. I went to the Oracle website and downloaded jre1.6.0_20 and installed it on my computer, but can't seem to get Firefox to load Java. If I download directly from http://www.java.com/en/download/manual.jsp, the plugin works fine but is the wrong version, and I can't find on www.java.com anywhere to download any of the previous versions. According to the help (can't post link because of spam prevention), I need to go into the Java Control Panel and enable it for Mozilla. I've done this multiple times, but every time I go in to the control panel and check the box, click Apply and Save, as soon as I go back in the box is unchecked.

Does anyone know either why the box is unchecked, or where I can download the old JRE that also is configured for Firefox?