link not updating after changing source location
 

I'm using Excel '03. The simple links from a master workbook do not update
to reflect changes to the source data in other workbooks. For example, the
link from workbook1 to A10 in workbook2 reads =SUM([workbook2]Sheet1!$A$10).
When I add a line of data to workbook2 I would like the link in workbook1 to
update autmatically to =SUM([workbook2]Sheet1!$A$11) but it does not. There
has to be a better way than manually updating each link. Please help.