Youtube Video

I went to YouTube to show somebody this Music Video


When I Watched it before the Sides of the Video had Big thick Black Bars.
Now it Blinks and Turns the Sides White.

I use FireFox.
Do you know if I Clicked on a Setting?

 

When I play the Video I posted on this Page it plays good.
And in my Living Room if I Stream it through my ComCast Box it plays good.

I will Run CCleaner and do what you say.
Thank you for getting back to me.

 

I Ran CCleaner and it did not Fix anything.
The Video stills plays with White Bars on the Left and Right Sides.

As you See in the Video I Posted the Bars should be Black.
And if I Play the Video on this Post above on this page they are Black.

And if I Play it through my ComCast Cable Box I can get YouTube the Bars are Black.
Is there a setting in FireFox I am missing?

 

It seems to be how this particular video displays in the default view when using Firefox. Switch to theater mode or full screen to view it with black bars.

 

Thanks if I use Theater Mode it works.