youtube used to have a tags option, which enabled change of ratio. But they removed it. My PC manufacturer MESH, said videos played 16:9 but they played the latest of music videos which are all...

when i was using windows 7 all my saved videos were 16.9 and filled my monitor. But, when playing them with windows 10, the same videos are 4:3, so they show black bars. Must be a windows 10 thing. ...

how do I get rid of black bars on either side of youtube videos, and downloaded video clips from other sites? Things were shown full screeen on windows 7.