After clicking on the Firefox icon on the system task bar so that Firefox is selected, you can use WinKey and the left or right cursor key ( "WinKey+right-arrow") to place the window on the right half of the screen, then adjust the boundaries in the normal manner. If you have multiple monitors repeat (3 positions per monitor) until Firefox is in your current window. On other Windows systems or if you have turn of one of the Windows 7 features, you can use "Alt+SpaceBar" to move/resize the window. Also see the following article, you may have an extension that is causing problems, so refer to the article for more information. :http://kb.mozillazine.org/Resizing_oversize_window