Dynamics NAV Native Database Deletion

If the database, database server and Client is installed in the same system, then Database can be deleted\replaced in the following procedure.
1. Open Navision Client.
2. Go to Create New Database window.
3. Select the database in the Database Name field, It will ask, do you want to replace the database. If you press yes then the existing database gets replaced.
We can't stop user from within Navision, as user can do it even without logging into the system.
Can we do some restriction at windows level. If you have the solution, please let me know in details.
Again we are using this environment in LS Retail, so we can't affort to use seperate system for database server.