how fix adobe flash player error in firefox

adobe flash player has been install ., but youtube videos in not 
playing in firefox.. lets fix it

step1:
make sure you have install from official site and the latest version
of adobe flash player



step2:
 now open firefox go to tools click on add on and now
click on plugins 

 step3:
now find shockwave player in the list and make sure it is enable
restart your firefox ...! and done