You are trying to watch a video on YouTube but all you get is a green screen like the one in the above screenshot. The audio portion is playing just fine but the Adobe Flash Player is unable to render the video.
If you refresh the web page, the ‘green screen’ problem might vanish temporarily but it is very likely to stage a comeback in your next browsing session. And this problem is not specific to YouTube but any video website that uses the Adobe Flash Player.
The fix is however simple. While you are on a video page, right click anywhere inside the Flash Player and choose settings. Now click the first tab that says Display (look for the monitor icon) and uncheck “Enable Hardware Acceleration.”
Refresh the page (hit F5) and enjoy the videos. The performance of playback in Flash Player might take a slight hit after you disable hardware acceleration but that’s obviously better than watching a video that only has sound.
I have done a quick screencast the explains the fix visually.