From Help on Password protect a worksheet or workbook:

1. On the File menu, click Save As.
2. On the Tools menu, click General Options.
3. Do either or both of the following:
4. If you want users to enter a password before they can
view the workbook, type a password in the Password to open
box, and then click OK.
5. If you want users to enter a password before they can
save changes to the workbook, type a password in the
Password to modify box, and then click OK.
6. When prompted, retype your passwords to confirm them.

Click Save.

If prompted, click Yes to replace the existing workbook.

You can also protect selected cell ranges.

HTH
Kevin Sprinkel

-----Original Message-----
I'd like to password protect a spreadsheet when the user
opens the file.
I know you can "protect" the worksheet, but i'd like to
have a Window
or something popup asking for the password before the
file actually
opens up...

Can this be done?