Error need Flashplayer already installed

Hello, I have flash player 11 installed on my computer. When I click on a video a note comes up stating thatI need to add flash player. I clicked on to add flash player, it installs it and message comes up stating it had successfully been installed. Went back to the video, clicked on it, and again it came up with the message that I need to install flash player. This is a recent thing, never had any trouble with it till now. I don't know what has caused it. Tried a number of fixes to no avail. Sure do need help. The computer is a Toshiba laptop running windows 7.