Google Chrome for Windows:
Type chrome:plugins in the address bar to open the Plug-ins page.
On the Plug-ins screen that appears, find the Adobe Flash Player listing. Check the status (Enabled or Disabled).
Select Always Allowed to always allow Flash Player to run.
Close the Plug-ins screen.
Firefox for Windows
Choose Firefox > Tools > Add-ons.
In the list of Add-ons, look for Shockwave Flash (another name for Flash Player) and check the status that appears to the right of the plug-in name.
Select Always Activate.
Close the dialog box.