1. Right click any toolbar and turn on Control Toolbox
2. Click the Properties button
3. Change the Visible property to xlVeryHidden
4. Press Alt+F11 and select your workbook in the Project window.
5. Choose Tools, VBA Project Properties,
6. Choose Protection and check Lock project for viewing and add a password.
7. Close the file and reopen it.
All passwords can be broken, but some are easier to break than others.