There is no particular file.

If you create a custom menu/tool bar, then that is contained with the
database...

The options to complete hide and keep people out of the ms-access interface
can easily be done using the tools->start-up options. Using those options
allows you to complete hide the ms-access interface (tool bars, database
window etc). Also, using these options means you do not have to bother
setting up security.

Try downloading and running the 3rd example at my following web site that
shows a hidden ms-access interface, and NO CODE is required to do
this....but just some settings in the start-up.

Check out:

http://www.members.shaw.ca/AlbertKallal/msaccess/DownLoad.htm

note how there is custom menu bars..and they will work on YOUR computer..but
you never set, or donwloaded the menus.

After you try the application, you can exit, and then re-load the
application, but hold down the shift key to by-pass the start-up options. If
want, you can even disable the shift key by pass. I have a sample mdb file
that will let you "set" the shift key bypass on any application you want.
You can get this at:
http://www.members.shaw.ca/AlbertKallal/msaccess/msaccess.html