Infinitejest

You seem to be asking two questions:

1) how to have blank cells not plot as 0.
2) how to get chart to automatically "pickup the new information as I enter
each week"

Question 1 deals with how Excel handles blanks. this post explains Excel
charts and missing data

http://processtrends.com/pg_charts_missing_data.htm

Question 2  deals with dynamic range names. I have two posts on the subject
that should help.

http://processtrends.com/pg_chart_tips.htm#Dynamic_Chart_Range_Names

http://processtrends.com/pg_dynamic_charts.htm

Kelly

To reach me by e-mail, use the spam proof address below
koday at processttends dot com

Infinitejest,
An easy way around this:
Build you graph to include only the last entered data.
Use chart wizard to make the graph that you want.
Save the file.
Next week add the new data.
Right-click on the graph to select it.
Select "Source Data" from the pop-up  window.
Select "Data Range" tab.
Edit the "Data Range' field to include the new data.
hth