Carole O wrote...
Excel 2003

Why does the date change? I copy 02/22/2005 and open a new
spreadsheet to
paste and the result is 02/21/2001.

The formatting for both cells is the same. Any ideas?

Different date systems. The first file from which you're copying dates
is using the 1904 date system. Your system defaults to the 1900 date
system, so when you open a new workbook and paste into it, the date
value remains the same, but it represents a given number of days from a
different initial (epoch) date.

You could either change your default date system to 1904, or after
pasting into the new workbook enter 1/1/1904 in a blank cell, copy it,
select all date cells, Edit Goto Special Constants, and Edit
Paste Special Values-Add to adjust all date constants to correct 1900
date system date serial values.