Download The Latest Flash Player

Simply visit http://www.adobe.com/software/flash/about/ and you will see the version information of the Flash Player installed on your computer.

A table of latest Flash Player version for different platform and browser is at the bottom of the page. (Google Chrome has own built-in Flash Player)
Compare your Flash version information to the latest version in the table and you will know whether you have the latest version or not.
If you do not have the latest Flash Player, you may download it from http://get.adobe.com/flashplayer/.