I am using Excel 2000 SP3 with (to me) a reasonably big spreadsheet (8.5Mb)
in which a set of functions such as the following worked and still work
properly:
=SUM(IF('JWCL-Current'!$H$4:$H$2966=$S$3,IF('JWCL-Current'!$V$4:$V$2966=$C40,'JWCL-Current'!K$4:K$2966,0),0))

I then copied the set of functions to another location and modified one of
the variables (as below)
=SUM(IF('JWCL-Current'!$H$4:$H$2966=$S$89,IF('JWCL-Current'!$V$4:$V$2966=$C120,'JWCL-Current'!K$4:K$2966,0),0))

The result is a displayed value of 0.00 instead of the correct value.

If I use the Insert, Function command on one of the cells containing the
modified formula, it displays in the dialog box the function as edited and
also shows the correct Formula Result for the cell. However, clicking on OK
in the function dialog box still leaves 0.00 displayed in the cell.

I have noted one difference between the original formula and the modified
one when displayed in the edit box at the top of the Excel window. The
original one is as shown above but is also enclosed in a pair of brace
characters, { and }, (although they do not show when I copy the formula from
the edit box to the above). These {} are missing in the edit box of the
modified formula. And entering them in the modified formula via editing
results in display of the formula in the cell rather than a value.

I would be grateful for advice as to what mistake(s) I may be making.
Thanks.

John