How do you force a cell to prefer numbers only?
I have a workbook that has certain cells that expect numbers to be entered.
If I try to enter something other than a number, I get a message stating,
"You must enter a number in this cell. ...Continue?" I've been trying to
find what's causing this message and how it knows if a number is entered or
not. I would suspect VBA, but I cannot find any code in modules or on the
individualtried sheets or ThisWorkbook. It's possible that the code is
hidden. Any ideas how I can find it?

Thanks,
Paul