I've gone through the download and install several times. The black Adobe window comes up, says install complete, but when I go to web sites that require Flash or to Abobe diagnostic sites, it showes no Flash installed.
It seems to be a browser specific issue. Try a different browser like chrome or firefox, it should work.
For fixing IE or Safari, lets follow below suggestions :
Run the Flash Player Uninstaller as applicable for your machine(i.e.Windows or MAC) and remove flash player.
Restart the machine.
Download and Re-install Flash Player.
Restart the browser and check.
You might also wanna check the below articles ::
Enabling Flash Player in Internet Explorer 9 : http://forums.adobe.com/thread/885448
ActiveX Filtering in Internet Explorer 9 : http://forums.adobe.com/thread/867968
Check the below link and see if it helps.