At the very least you can remove users' "delete" permissions from the mdb
*file* (not the host folder).  Next you could remove all startup options,
provide custom menus and toolbars, and disable the bypass (shift) key.

That should be enough to keep most casual snoops out, but if any of them are
Access savvy then you might want to consider applying user level security.
This is a complex topic with a steep learning curve but it will keep out all
but the determined hacker with special tools.  If you want to apply ULS then
read the FAQ (link on my web site).  Top tip:  make BACKUPS of you files
first, it's easy to lock yourself out when you're learning ULS.

Good luck.
Keith.
www.keithwilby.com