Your System Details List shows multiple Flash plugins.

1. Shockwave Flash 17.0 r0
2. Shockwave Flash 19.0 r0

You can find the installation path of all plugins on the about:plugins page.

• http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins

You can check the Flash player installation folder for multiple Flash player plugins and remove older version(s) of the plugin (NPSWF32) and possibly (re)install the latest Flash player.

• (32 bit Windows) C:\Windows\System32\Macromed\Flash\
• (64 bit Windows) C:\Windows\SysWOW64\Macromed\Flash\

See also this about uninstalling Flash players:

• http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html

Note that this will remove all installed Flash players.

Ok, I used "about:plugins" and I found the file of the Shockwave Flash 17.0 r0. Now what? I want to uninstall that file without uninstall all Flash Players in my PC. :(

You can delete this file via File Explorer and only leave the latest Flash player file (NPSWF32_##_X_X_XXX.dll) in that folder.

You can also check the Windows registry.

• HKLM\Software\MozillaPlugins\@adobe.com/FlashPlayer

• https://developer.mozilla.org/Add-ons/Plugins/Gecko_Plugin_API_Reference/Plug-in_Basics#How_Gecko_Finds_Plug-ins

It's done. Thanks for your help! :)

You're welcome