Excel changing 2002 dates to 2121?

I have a user that is trying to enter date data into a spreadsheet, have formatted the cell to 00/00/00 format, but when entering say 10402, Excel will convert to 6/23/28, that is 1928. If I set to use the 1904 date system, it makes it 6/24/32 ie 1932. I have tried this with Excel 97 and 2000 on both win 98 and win xp systems with no change, date settings in the BIOS are OK. Any Ideas?