Mac keyboard suddenly switched to French

Hi guys, I'm new to these forums so if this is in the wrong place, sorry!

Last night as I was shutting down my Mac, it suddenly came up with three language options - Spanish, French and Australian English, and selected French. Of course, it shut down before I could do anything, and now I can't log in as no matter what I try, I can't make an @ symbol on the AZERTY keyboard. Any ideas? Or anyone know the shortcut to change it back? The option comes up frequently (usually when I'm in the middle of assignments) so I figure something must get hit.

Thanks so much!

I searched and as far as I can tell there is no @ symbol on the French keyboard. But here's what you can do: Boot your Mac from your original install recovery DVD. When the install information comes up, select English (Australian English as the language of choice). Then, instead of installing, select the top menu item Utilities. Choose to change your password but instead of a new password, use a null (carriage return). Reboot your computer. It should now allow you to get in without a password and from there you can switch the keyboard back to Australian English.

If the French keyboard setting is anything like the French Canadian one, I believe it's Alt-2.

Most other websites seemed to go for the alt-2 option, but strangely enough it was alt-\. Eventually found this out after a couple of hours of searching and hitting every key combination. Thanks for the help from both of you, though! I've disabled the other keyboards so only Aust English is available, but it's good to to know about the reboot/utilities option as well.