Either of these would work *Drag the edges of the windows to resize, drag window by title bar to move * On Windows use "Alt+SpaceBar" to move and resize window, especially if the title bar is not accessible because the window is too high. Move allows you move window. Size (resize) allows you to resize in a vertical or a horizontal direction but not at the same time. You can use the mouse or the cursor keys with move or size. After you have the size you want, suggest you use File > Exit or "Firefox" button > Exit, and then restart Firefox. More details in http://kb.mozillazine.org/Resizing_oversize_window

See also: *http://kb.mozillazine.org/Corrupt_localstore.rdf

Many thanks for your help.