Adobe Flash Player has been crashing with Firefox for 6 months

When I go to https://helpx.adobe.com/flash-player.html Adobe flash player works fine but then when I go to another website like https://www.groupon.com/deals/the-tangiers I’ll get a Window popup that says that "Adobe Flash Player 21.0 r0 has stopped working" and the problem details box as shown below:

Problem signature:

Problem Event Name:                        BEX

Application Name:                             FlashPlayerPlugin_21_0_0_213.exe

Application Version:                           21.0.0.213

Application Timestamp:                    570336dd

  Fault Module Name:                          StackHash_27eb

  Fault Module Version:                        0.0.0.0

  Fault Module Timestamp:                 00000000

Exception Offset:                                2a8892cd

Exception Code:                                  c0000005

Exception Data:                                   00000008

  OS Version:                                          6.1.7601.2.1.0.256.48

  Locale ID:                                             1033

Additional Information 1:                  27eb

Additional Information 2:                  27eb358fe674a6f15dafe56d42bb9bf3

Additional Information 3:                  2f06

Additional Information 4:                  2f06c18113e6d7c00e6b91fa1fde84b6

And a minute or so later another popup box says "Warning unresponsive plugin.  Shockwave Flash may be busy or itr may have stopped responding.

What do I do to prevent this from happening – it’s been going on for 4-6 months?  I’m using Firefox 45.0.2 on a PC with Windows 7 Professional 32 bit with service pack 1 on a 3.2 GHz computer with 3.5 GB of RAM.  I’m using flash player version 21.0.0.213.