Have you ever had to support users with a different national keyboard than yours?
If so you may have noticed that national keyboards can vary quite a lot!?
Anyway, here is a few links to graphical depictions of national keyboards, then you at least stand a fighting chance 🙂
http://en.wikipedia.org/wiki/Keyboard_layout
http://msdn.microsoft.com/en-us/library/cc195104.aspx