Excel 2007

I have a workbook that contains 6 checkboxes. The checkboxes work fine for
me (I developed the workbook), but they don't work for other people, and we
are all running the same version of Excel. At first I thought that maybe
there was some macro programming behind those checkboxes and that macros
were simply turned off for other people, but there are no macros in the
workbook.

Anyone have an idea as to what might be causing this problem?

--Tom