I have an issue where whenever the cells on a worksheet are selected for
re-calculation, it gets "stuck" at 0% and causes Excel to stop responding.

The spreadsheet is designed to do the following:
- First worksheet lifts data from another spreadsheet via link function.
- Second worksheet calculates totals based on the data in the first
worksheet. For example, calculations include things like:
=SUMIF('First Worksheet'!D:D,"Michael",'First Worksheet'!I:I)
This is done to sum all of Michael's entries and is repeated for each person.
There is then a total to sum entries for groups of people.

I have tried re-calculating based on auto and manual with the same results.
The CPU appears to max out at 100% and the application hangs.

I am running WinXP SP2, Excel 2003, P4 2.4Hz, 512MB RAM and have downloaded
all Excel 2003 updates.

Just as a sidenote, if I re-create the formula in a new cell it calculates
instantly. Is it possible that the formulas need to calculate in a certain
order and this is causing the problem?

I would appreciate any help you can offer with this problem.

Marina