Sorry if this is the wrong forum (mods, please move to the correct forum if you want), but since there are many people around here who publish to the web, I thought I would share with you some problems I encountered with:
This is a terrible combination. After installing Flash Player, Firefox often comes to a halt, not responding anymore and the only solution is a complete removal of the Flash Player. This applies to all 10.x and 11.x versions of the Flash plug-in. In TaskManager or Process Explorer this weird behavior is shown as two instances of the plug-in running.
In Explorer, navigate to C:\Windows\SysWOW64\Macromed\Flash and open the file 'mms.cfg'. Add a single line:
to this file and save. Now restart Firefox and your problems have gone.
Never noticed this behavior myself.