First of all, the video is played with IE or other browsers,

When the video can not be played in full screen, please check whether the site has a full-screen function;

Generally will be directly displayed in the video under the right side of the progress bar, that is, the whole video has a full-screen button in the lower right corner;

If not, you can click on the upper right "Maximize" button and then press and hold the keyboard Ctrl button. The whole video has a full-screen button in the lower-right corner;

If not, you can click on the "Maximize" button on the top right of the browser, and then hold down the Ctrl key of the keyboard, scroll the mouse up to zoom in on the web page, and then adjust the video to the best screen can be;

The next is the video in the player, can not be full screen, actually depends on the function of the player itself.

Some players don't have full-screen capability, but there are shortcuts for each type of player.

Some videos on your computer are fixed-size, not resizable; no matter which player you use, you can't go full screen.

The only way to play these videos in full screen is to lower your screen resolution to the appropriate size for the video.

There are many different kinds of videos, so it's important to distinguish between them, and there are many ways to play them, so you can't stick to one.