I have some workbooks that had been Excel 2000 and are now Excel 2007. They
seem to work fine but at the time the 2000 workbooks were saved as 2007
workbooks, many of the chart names were converted to numbers, e.g., "chart
18" "chart 41". I have tried to rename the charts to indicate their subject
matter and the new names initiailly take. But once the workbook is reopened,
after having been saved and closed, the new names have disappeared and the
number names have reappeared. Can anyone explain to me what is going on and
what I can do about it?

Note: I have renamed pages using two different methods: 1) right clicking on
the name tab itself 2) renaming via chart tools/layout/properties, and the
problem arises either way.

Thank you in advance,
Geoff