Your PlayStation 3's Web browser puts all the glorious cat videos the Internet offers right on your TV. Many videos use Adobe Flash Player to play in the browser. Sony assures that Flash Player is already included with system software 2.50 and newer, but you'll have to give permission to run the plugin upon first encountering a Flash video. If you don't see the prompt, resetting your PS3's system settings also resets the prompt.
Watch Flash Videos
Using your PS3's Web browser, visit a website with a Flash video. When you see the "Do You Want to Run the Plugin?" prompt, highlight "Yes" and press the "X" button. If you don't see the option appear, you may have accidentally told your PS3 not to run the plugin in the past. Restoring the system to its default settings resets the message, giving you another opportunity to allow the plugin.
Restore Default Settings
Navigate to "Settings" from the Home screen. Select "System Settings" and "Restore Default Settings." Press the "X" button, then select "Yes" to confirm. Restoring system settings will not erase any data like games, saves, movies or music. The process will reset all system settings, so you will have to go through the set-up process to restore date and time, video, and network settings. When finished, select "System Update" under the Settings menu to ensure your PS3's software is up-to-date. The next time you visit a website with a Flash video, you'll see the prompt to enable Flash player.