PowerPoint Links to Excel

I have a Power Point 97 file that is linked to several Excel 97 Charts. The links do not update unless I open each chart in Power Point. Also, if the Power Point and Excel Files are deeper than folder 3 levels Power Point cannot locate the links.

I would like to have the links update automatically without having to open each chart individually.

Is there a problem with links and how deep in the directory tree the files are located?