Google with something like
excel password protection
to get lots of ideas

There are two different meaning to your question:
1) you can project the file on saving so that a password is need to open
2) you cam protect the workbook so no one can make changes

Do some reading of the sites found by Google and please come back for more
info
best wishes
--
Bernard Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme

"Debbie B" <Debbie wrote in message
...

Debbie, here is a worked example for you in EXCEL 2007:

1. I have EXCEL running already.

2. Hit CTRL N to launch a new Workbook.

3. Single left hand click on the Office Button (top left hand corner).

4. Prepare / single left hand click on Encrypt Document.

5. Encrypt Document window appears.

6. Enter a password the in box, for example:-

SatAug1_2009

7. Single left hand click on:-

OK

8. Enter the password again, for example:-

SatAug1_2009

9. Single left hand click on:-

OK

10. Ctrl-S

- to save the new file.

11. Give it a name, for example:-

c:\excel\sat_aug_1_2009

12. Single left hand click on:-

Save

TO CHECK THAT THE ABOVE HAS WORKED

13. Single left hand click on:-

Office Button (top left hand corner)

14. Close.

15. Single left hand click on

Office Button (top left hand corner)

16. Select:-

sat_aug_1_2009.xlsx

- from the Recent Documents section.

17. Enter the passwrod:-

SatAug1_2009

18. Single left hand click on:-

OK

- and the file will open.

19. You might find the following helpful as well:-

http://office.microsoft.com/home/vid... =EXCEL&ver=12