Excel 2003 charts will not auto update to new data. Ideas?
 

When I input new data in a cell it over top of data that is already in within
the cell range of my chart, the new number will not show within the chart.
The chart simply does not update unless I close the file and then open again.

As a side note I'd like to mention:
1) The data that I change is already withing the cell range of the chart.
2) The data is withing the same work book. This is not a matter of linking
books.

Any ideas?