I have found that in opening older Excel files in Excel 2007 there might be some text boxes that are not used but require a lot of space and processor time to render. You can see if there are any in your file by first selecting the "Page Layout" tab and then "Selection Pane" on the ribbon. A "Selection and Visibility" window will open and if there are text boxes or other objects you will be able to see them and delete them if necessary.
Hope this helps...
Hope this helps...
