Splash screen?
Just create a .bmp with the same name as your db and store it in the same directory. When you load up access you'll see this .bmp...sometimes it flicks on and access opens right away..since PC's are so fast. If you want a longer (3-5second) splash screen youll have to create one and open it directly.
I presume that you mean the database window, or do you mean the Access window (blue bar at top - can't remember its name )?
If you mean the database window, then go to 'tools' on the menu bar, choose 'startup', then choose the name of the form that you wish to appear as default in 'Display Form'. Make sure you uncheck 'Display Database Window'. HTH.
Edit: You could make your own custom menu - I guess that you want to prevent users from accessing certain things?