Need help recovering corrupted outlook express address book

So my dad’s address book won’t open. First, outlook express says that the address book isn’t installed properly, and then that the address book file is corrupted. It has important business contacts, so its imperative that I save the data. How can I get into the file? I can open it in notepad and I see a lot of the text, but its mostly names and I can’t find any email addresses. Any help would be greatly appreciated.