Susan's Word documents have become corrupted on her desktop. Leo says that there may be an issue with Office 2000 that's causing it. Leo thinks that she may have different versions of the same file and that when she saved it, one version got corrupted. She had copied and pasted from a PDF into Word, and could have caused an issue.
The consensus from the chatroom is that the file is in .docx format, and it's not supported by the version of Office that she's trying to open that with.