As posted often in the newsgroups, there is no backdoor password for Access.
If there were, then the security would not be of much use.
If you are using a UserID and Password, then you might try joining a default
workgroup, or one without any passwords set up. People often build UserIDs
and Passwords, but never bother to actually secure the database file. This
means that it appears to be secured (on the computer where it was created),
but when you join another workgroup with normal admin rights, you can get to
everything. It is pretty common for folks to skip the many important steps
in securing a database. To test this, simply join the default workgroup and
see if you can get into your file.
You might also try to create a new database and import all the objects.
If none of that works, then you would have to pay a service to retrieve your
data or locate software that would do it for you. Both of those options
typically include a fee.