Flash player (Safari Internet plug-in) (not responding), running El Capitan

Often is the case that when searching the web, I get the spinning beach ball or the screen freezes.  When I check the activity monitor, I find that either flash player is using a large percentage of the cpu or a message states that the Safari plug-in is not responding.  I have tried rebooting but this provides only a temporary fix.  My iMac is rather new (21.5 inch, late 2012 with 16 GB memory, Graphics NVIDIA GeForce GT 650M 512MB. I am running El Capitan, 10.11.2  ......... The Adobe Flash Player is 20.0.0.267

I have read about this problem for people earlier in 2015 when running Yosemite but not as related to El Capitan.  Any help would most certainly be appreciated.  I am a novice in fixing computer issues.