I have several Excel workbooks that were originally created in Excel 2003 or
earlier versions. Once I installed Excel 2007 early this year, I've been
having problems with formulas that were working correctly suddenly stop
functioning.

First, a REF! error shows in the cells. The error message says that deleting
or moving a column has caused a problem. I then go in to the formula to put
in the correct referenced cells. The Results while I am in the formula window
show the values correctly, but when I close the formula window then only the
formula shows in the cells, not the resulting value. The only fix I have
found for this is to delete the entire column, insert a new column and put
the formula in again. This has been happening all year on occasion, but I've
always been able to finally fix the problem.

Tonight, however, deleting the column and inserting a new one did not help.
While building the formula the Results are correct, but once I finish the
formula, only the formula shows up in the cells, not the value.

Can anyone help me with this?