well I gave up. I tried different players and 1 out of 5 worked. the KM player was the one I use now. Thanks for the suggestions.

When I click taskbar settings nothing happens. Another account auto hide works.

In Windows 10, you can auto-hide the taskbar by:

Right-click on taskbar -> Taskbar settings -> check "Automatically hide the taskbar in desktop mode"

Note that if your taskbar is set to auto-hide, it will appear when your mouse cursor is down there. So make sure your mouse cursor isn't at the bottom of the screen when watching full-screen videos.

I am using Windows 10

I assume you're using Windows. Which version? 10 or 11?

There's a setting to auto-hide the task bar. Do you have that turned on?

In Windows 11, you can get to that setting by:

Right-click on task bar -> Taskbar settings -> Taskbar behaviors -> check Automatically hide the taskbar.

My taskbar doesn't hide when I play a video full screen now.
Any help would be very appreciated. :TY1: