Security is set up through a combination of the application MDB itself, and
a System database (.MDW) file. It is not PC related, nor associated with
msaccess.exe itself. To learn how to apply Access security properly, read
the Access Security FAQ thoroughly several times, make sure you don't skip
any steps (and work with a copy of your database, just in case)

http://support.microsoft.com/support/access/content/secfaq.asp

BTW, you may want to rethink your design a little. You should have your
application split into a front-end (containing the queries, forms, reports,
macros and modules), linked to a back-end (containing the tables). Only the
back-end should be on the server: each user should have his/her own copy of
the front-end, preferably located on their hard drive.