I don't even see your Flash plug-in the current version is 10.3.181.34

• http://www.adobe.com/software/flash/about/

Watch out for crapware that may be offered along with Flash.

Fire Bug is problematic extension and should be disabled unless you are actively using it.

Check your plug-ins http://www.mozilla.com/plugincheck/

Most of the bad bugs seem to have been removed from Flash, one problem though that might affect many is hardware acceleration, I turned it off through right-clicking in the adobe flash viewer and then through settings, but the option is in Firefox Tools > Options > Advanced > General, since mine is On, the setting in Flash probably only applies to Flash.

Doubt that you would install a third party search , but

KwiClick a search add-on and may interfere with Flash (Q836717)

I use the latest flash plug-in 10.3.181.34.

The problem manifests itself even if Firebug completely delete. Other extensions I do not have installed.

Of hardware acceleration, I tried. No effect. I do not think the problem with flash. In other browsers running smoothly.

The problem I have managed to remove. Way it RelevantKnowledge. (http://www.relevantknowledge.com/Home.aspx )

Thank you for your help