If you running a 64-bit Windows you may recognize you can use 32- as well 64-bit Internet Explorer. In the past only Adobe Flash Player for 32-bit Windows was available. Just a release candidate of the 64-bit Adobe Flash Player was available. So you needed to install both to get Flash Player support on your browser.
Now Adobe released the final version of a 64-bit Adobe Flash Player.
You need to uninstall all previous Adobe Flash Player versions from your Windows and install only the 64-bit Adobe Flash Player version, which also contains the 32-bit Flash Player version if you use also your 32-bit Internet Explorer on your box.