Grandma,
Is this happening to text in drawings, or to text in dialogs? Texts in drawings are unicode since ArchiCAD 9 (other parts of ArchiCAD became unicode later), so this really should not happen. The only thing I can think of is that you don't have the type of font installed on your computer, and the proxy font does not support cyrillic. Make sure you have the right fonts.
If the problem happens in dialogs, please check if this helps:
http://archicadwiki.com/Bugs/Cyrillic_font_problems
Gergely Kmethy
VP, Customer Success, Graphisoft