I have researched everything I could find and nothing helps. I uninstalled Flash Player because I was getting frequent 'shockwave has crashed' problems when I played some games. Now, I can't reinstall it. Tried many times; turned off my firewall; etc. Flash is not showing in my control panel as an existing program (because I uninstalled it), but I get the message "only one instance of this ap can run" when I try to complete installation and run it. I have Windows 7 and use Firefox. None of the related articles has helped me. When I click on "check if Flash is installed" it tells me not installed or not enabled. When I try to enable it, Flash or Shockwave is not even listed under Tools > Add-ons in Firefox. I have no idea what is left to try.
By the way, it appears that I can watch videos. But I can't access my Pogo games any more. Says Flash is out of date. I'm very confused.
FINALLY! This worked. Thank you. Why on earth do you need a special (and secret) Adobe uninstall site? Crazy. Nothing told me that Flash was still installed in some secret computer place causing problems. (I uninstalled using the Control Panel.) People like me who are barely versed in computer inner workings are at a huge and uncomfortable disadvantage.