To make your database "user proof" just follow these simply steps:
In the tools ---> startup menu specify a form to display when starting the database. Uncheck "display database window", "Allow full menus", "Allow Built-in toolbars", "Allow Toolbar/menu changes". Then click on the advanced button and uncheck "Use special access keys".
After doing all that, the only way you'll be able to get to the underlying database will be to "shift into" it. Be careful! This is the only way you can get into the database as well.
If you also want to display the shift trick (recommended with nosy users), read this incredibly useful FAQ. faq181-143.
Maq B-)
<insert witty signature here>