I suspect that the Taskbar Autohide was enabled for a while and the app borders were expanded to take up more of the screen real estate. Then the Taskbar Autohide was disabled and the app borders are still expanded. You should be able to grab the borders and reposition them so this condition does not happen. Just try to resize the borders and see if your problem is solved. Or perhaps re-enable Autohide (right click Taskbar and choose Properties, then check Autohide.