One place to check is
chrome://plugins/ in Google Chrome. Just type that into the address bar and hit ENTER. You should see a list of all the plugins that are available through Chrome. If you've downloaded and installed Flash, you should see two entries there. One for your own install and one for the version of Flash that comes bundled with Chrome. It will also tell you there if the plugin is disabled or enabled.
Also if you go into Settings in Chrome and search for "Flash" it will highlight the "Content Settings..." button under Privacy. Check Plug-Ins under there and see whether "Block all" has been chosen from the available "Run automatically|Click to play|Block all" options.
Another thing to check for are ClickToPlugin or ClickToFlash extensions that can be set to selectively block Flash plugins. You can find the installed Chrome extensions with "Extensions" from the Window menu and the installed Safari extensions with "Safari Extensions..." under the Safari application menu.