Windows Taskbar on the bottom of the screen is blocking the exit button

Right-click an empty space on the taskbar. If "Lock the taskbar" has a check mark next to it, the taskbar is locked. You can unlock it by clicking Lock the taskbar, which removes the check mark.

To move the taskbar:  

Click an empty space on the taskbar, and then hold down the mouse button as you drag the taskbar to one of the four edges of the desktop. When the taskbar is where you want it, release the mouse button.    

Note:  

To lock the taskbar into place, right-click an empty space on the taskbar, and then click Lock the taskbar so that the check mark appears. Locking the taskbar helps prevent it being moved or resized accidentally.