importing old outlook files

I changed my operating system from mellineum down to win
2000. I had to do a clean install. So I saved my old
address book and old in-box mail.

I have tried to import these files but my "new" outlook
won't do it.

What are my alternatives?

is there another way to import?
Can I alter the file extensions?
Is there a way to open thse files and copy them one-by-one
into a new folder that is readable by outlook or word?

Thanks