Register your search on a Reunion Registry. This is a system for matching persons who desire contact with their next of kin by birth. This file contains information about your adoptive family at the time of your birth. Even if it is an amended certificate, it may contain important clues. Locate the office where you can order your birth certificate at Centers for Disease Control and Prevention Join a Support Group .
Support groups provide assistance during and after the search process.
They probably moved, and privacy laws limit your resources to trace living persons. They contain names of adults, their addresses, and occupations. There are a number of phone directories on the Intenet. One of the easiest to use is Switchboard. Your birth parents may have married - either to each other or to someone else.