 <p>To stop the video from playing you need to make use of the keyboard commands the you tube player recognizes to control the player. They are limited...</p> <pre><code> Spacebar : Play / Pause Arrow Left : Jump back 10% in the current video Arrow Right: Jump ahead 10% in the current video Arrow Up : Volume up Arrow Down : Volume Down </code></pre> <p>So what you can do is use </p> <pre><code> SendMessage(FlashPlayer.Handle,WM_KEYDOWN,VK_SPACE,0); SendMessage(FlashPlayer.Handle,WM_KEYUP,VK_SPACE,0); </code></pre> <p>to fake a key press and get the youtube player to, in this example, pause or resume play.</p>