How to Lock Cells in Excel

Locking and Protecting Cells: Excel 2003

1. 
   Open the Excel document that contains the cell or cells you want to lock.
2. 
   Select one or all of the cells you want locked.
3. 
   Right-click on your cell selections, and select "Format Cells" from the drop-down menu.
4. 
   Click on the "Protection" tab.
5. 
   Place a checkmark next to the field labeled "Locked."
6. 
   Click the "OK" button.
7. 
   Click on the "Tools" menu at the top of your Excel document.
8. 
   Select "Protection" from the list of options.
9. 
   Click on "Protect Sheet."
10. 
    Place a checkmark next to the option labeled "Protect worksheet and contents of locked cells."
11. 
    Type a password at the prompt for "Password to unprotect sheet," then click "OK."
12. 
    Reenter your password at the prompt for "Reenter password to proceed."
13. 
    Select "OK." All the cells you selected will now be locked and protected, and can only be unlocked going forward by selecting the locked cells, and entering the password you initially set up.