Check the plugins installed and activated by default through "Tools -> Add-ons" -> "Plugins" or "about:plugins"
"Check to see if your plugins are up to date"
vp1. Some default plugins should be there, at least contain:
- Note: maybe various from different distribution version, SLED12 for example* Shockwave Flash IcedTea-Web Plugin Div X Web Player iTunes Application Detector QuickTime Plug-in VLC Multimedia Plugin
vp2. Firefox will launch "Mozilla Plugin Check" web page, and list your plugins which need to be updated.