How do I stop the pop-up from asking me to download a new version of Flash Player on my Mac?

I keep getting a pop-up window from Adobe saying "There is a new download available for Flash Player, do you want to install it now?"  When you click on the install button, of course you get a message saying "Flash is no longer available for download".  Then a day or so goes by, and the same pop-up comes back again asking "There is a new download...."

Does anyone know how to stop this?  Being going on for months now, and I"m sick of closing the window