

The default key combination to rotate the layout is the Ctrl+Shift or Alt+Shift combination that is used in Firefox for menu items, so it is quite possible to change the layout accidentally.You need to do that while Firefox has focus because Windows remembers the keyboard layout setting per application.Check the keyboard language (keyboard layout) setting for the application that has focus via the icon on the Language bar.You can do that via the right-click context menu of the Taskbar: Toolbars > Language Bar.Make sure that you have the Language bar visible on the Windows Taskbar - HOW TO: Use the Language Bar in Windows XP.

Windows remembers the keyboard layout setting per application and you may have changed the keyboard layout by accident via a keyboard shortcut. It is possible that you have switched the keyboard layout by accident by using the key sequence to rotate the layout.
