[AccessD] Access Security mess

Hi folks, help please.
I know ****** all about Access workgroup security and have been handed a problem
with it. Great.
The situation is that this db has several users who can access it fine, but now
they need someone else to do so. It seems like only an Admin user can do that
but I don't know, and they don't know, how to log on as Admin. Is it done with a
command-line switch? If so can someone spell that out for me? Then the next
issue is going to be that no-one knows the admin password. What can I do about
that? Anyone got/know a pw cracker for this situation?
Oh and there's this. The site has migrated to a different domain. As I say, that
hasn't stopped the users using the db, but might this have repercussions on the
security or is Access security independent of all that? Just though I should
mention it.
Help would be greatly appreciated.
Andy