I don't believe you can actually lock the Navigation Pane. You can, however, minimize it or hide it completely. Does the code in the screenshot below help with what you want to do?

Thanks Mr. Kevin, i have applied the code but what i actually want to is i have a menu form when it loads i want to Disable the Display Navigation Panel and also Disable Layout view , Disable Design Changes and also Disallow full menu and Disallow Default Short cut Menu , Disallow Built in ToolBars ( in the Current Database) Menu.

Thanks alot

go to the ribbon click file  then select options then choose current database from there you can untick the check boxes for navigation pain also untick check box for allow full menus and the same for allow default shortcut menus
you will not be able to right click on your forms to make design changes hope this helps
i apologies if any of the information i have provided is incorrect i am still learning my self