You should be able to load the office 97 stuff directly into office 2000...
However, I have had issues with doing this before so what I had to do was open up the files in Office 2000 and then save as rich text format and then open up a new blank document for each one and then copy and paste all the text from the new rich text docs to the blank document.
Then save the new document as office 2000 format.
That's a long winded one I know but it sorts out most bugs that occur from just using the office 2000 file conversion process on it's own.