It is really annoying whenever you try to watch a video on YouTube and you ended up only in getting a green screen. In a meanwhile, you will get the audio but Adobe Flash Player fails to deliver the video properly.
Refreshing a page might have solved the problem for you but there are chances that in your next browsing session the problem may comeback. This problem is not only limited to YouTube but all the other websites which make use of Adobe Flash Player.
The long term fix of this problem is quite simple. Whenever you get this green screen while playing a video, simply right click in the Flash Player and opt for Settings. Next you will get a small window with first option saying Display. On Display tab you have an option checked saying Enable Hardware Acceleration, simply uncheck this option.
You’re almost done. Hit the Refresh button or hit the F5 key to refresh your page and you will now have sound as well as video. Well, by doing so, the performance of playback may have a bit of drop, but watching a video with sound is far better than just hearing the sound with green screen.