How to read "REALLY OLD" CDR files

I have a couple of 15-year-old CDR files that I need to edit/update, but CorelDraw 12 won't open them -- just gives me an error message saying that they were created with CorelDraw version 1 or 2, and it can't open them.  Does anyone know a way I can update the format of these files so that I can edit them with recent versions of CorelDraw?  Before you ask, I no longer have any version of CorelDraw older than version 12.