video's in lower right hand corner?

I usually use Edge, and when I am on a page and scrolling down a small video will appear in the lower right hand corner. I was looking for a way to stop this and one site suggested it was flashplayer? I have checked for viruses and there are none.

On Facebook at time a video playing can appear on the right hand side.

I can x out of the video's but prefer them not to be detached from the window. Some are automatic.

Any suggestions if it is flash player, or a setting, or something else.

thanks Bruce