Recent crashes of certain multimedia contents (this includes Youtube videos, certain flash games and other applications) in conjunction with Firefox are most probably caused by a recent Flash update and/or a malfunctioning browser plugin such as Real Player. In order to remedy the problem, please perform the steps mentioned in these Knowledge Base articles: * [[Flash Plugin - Keep it up to date and troubleshoot problems]] * [[Flash 11.3 crashes]] * [[Flash 11.3 doesn't load video in Firefox]] Other, more technical information about these issues can be found under these Links: * http://forums.adobe.com/thread/1018071?tstart=0 * http://blogs.adobe.com/asset/2012/06/inside-flash-player-protected-mode-for-firefox.html Please tell us if this helped!

By the way, though reverting to 11.3 has solved the problem it reads that the version is vulnerable. Is it enough to use full COMODO inernet security in order to prevent possible damage to my system?