Access Access database

[amoss]

I am trying to produce an access database for client names and addresses to be entered using a form but I want the establishment address to be automatically completed if the establishment name when entered is in an existing table of names and addresses. I want to store the address in the new client database table and be able to add a new address if the establishment name does not already exist.

I have tried various ways of doing this including dlookup, and on afterevent with no success. It seems a very logical thing to do but I cannot get Access to do it. I would be grateful for any help.

Many thanks