Disappearing chart
 

I have a workbook that was created in Excel 2003 and converted to 2007. I
had about 130 lines of data in three columns that were plotted on a line
chart (one date column for the X axis, and two columns of numerical data
plotted on separate lines). The data was on one tab and the chart on
another. I entered a new line of data every morning (OK, I was tracking my
weight, but that's not important), and about 4 days ago, the chart suddenly
disappeared. The tab is still there, but it is completely blank.

I tried copying my data to a new workbook and recreating the chart. The
chart appears fine when it's created on the same tab as the data, but when I
"move" it to a new tab, that tab is blank.

Any ideas here? I miss my chart!!

Suz