Here is a weird situation...

I received a workbook for a project. In one worksheet I have data fin two
different categories for each month of year for 1999 to 2007. I am taking the
ratio of the totals for each month of each year for each category. In a cell
I am typing =e7/b7, but the result shows =e7/b7. I checked the formatting of
the cell, and it was set to "text." I changed the formatting to %, yet the
result is still showing =e7/b7. I move the formula to various blank cells and
change to formatting to %, yet the result still shows =e7/b7. Also, I copy
all the data and paste it into a new workbook...and I am having the same
issue. I am using Excel 2003...can anyone help me determine what is wrong? As
far as I know the worksheet is not protected, and I am not even sure that is
what would be causing the issue if the worksheet were protected. I am able to
change numbers in the original data without any problem, either.....