Word 2000 – Page x of y

Users have created documents with multiple pages. The header is on each page with page x of y. When you first open the document the page x of y shows “Page 1 of 1” when it should be “Page 1 of 16”. Once you move around in the document it updates to 1 of 16 on the first page. What do we do to have the document show 1 of 16 when first opened?