Why won't any adobe download continue to run on Firefox? Even if it initially begins, it continually shuts down. Now won't start up at all. Firefox recommends returning to version 10 of flash but cannot download it.
Downgrading to a version of Flash Player with known security vulnerabilities is terrible advice. You should always run the most recent version of Flash Player.
If you're struggling with Firefox, you might consider Google Chrome instead (http://www.google.com/chrome/).