Let me help you with this.
I would like to get more information about your system configuration so I can have a clear picture of the issue.
Can you please provide your dxdiag report here?
How to get it?
Dxdiag Report: Type dxdiag in Start Menu> open> Save> Attach using Advanced Editor Options.
Can you also provide a link as an example of the embedded video you are trying to play?
Thank you for the information.
Can you please try updating the graphics driver?
Make sure you have the adobe flash player up to date, this could do the trick.