» Prevent Unauthorized Opening of Workbook

To enter a password:

1. From the File menu, select Save as.
2. From the Tools dropdown list, select General Options (in Excel 97 select Options).
3. In the Save Options dialog box, enter passwords into Password to open and Password to modify boxes, and click OK.

Excel 2002 and Excel 2003 offer additional options:
1. From the Tools menu, select Options, and then select the Security tab.
2. Enter passwords in Password to open and Password to modify boxes and click OK.

Screenshot // Prevent Unauthorized Opening of Workbook