How do I get web sites to recognize I do in fact have flash player downloaded?

Every time I go to web sites that require Flash Player, I get a message saying I need to download flash player. I have downloaded like a zillion times %26amp; still get this message

How do I get web sites to recognize I do in fact have flash player downloaded?
do you have vista? theres a problem with vista and flash. you have to uninstall it, delete the folder with it. then redownload and install. its a pain. if you have XP, it wouldnt hurt to try the same steps.