When I open my Excel 2000 workbook in Excel 2003, I get all these green
comment tags that say "This cell contains a formula, and is not locked
to protect it from being changed inadvertantly."

If some cells were locked, and others were not, then this would make
sense to me. But it seems strange because when I select all cells and
open the Format Cells dialog box, the Locked checkbox (under the
Protection tab) is not checked (or even grey-checked), meaning none of
the cells are locked. Why is Excel 2003 warning me that formulas are
not locked when NONE of the formulas on the worksheet are locked?
Thanks.