ISO Son Born in Cali, adopted in Oregon (Complicated)

I am searching for my son who was born in Los Angeles, California on 5/30/1976 and named Steven James Walters. I was 16 and my father had thrown me out. I rented a room from some friends and one of their Mother's talked me into giving my son up to someone in her family who lived in Oregon when he was 9 months old (2/77) She said they were both doctors and could not have children of their own. She was a very nice woman and I trusted her. We (his father and I - we were not together though) went through an attorney for a private adoption that this woman arranged for us. I cannot remember the attorney's name but I know his office was in Garden Grove, California. I have been looking for my son since his 18th birthday!!! All I know is that (heard from a friend, who could have been wrong) that they renamed him Zachary or Zachariah. I can find NOTHING! It seems he has vanished off the face of the planet! Now, after lurking here for a while I am very frightened that they changed his birthdate as well. I don't know which state I should concentrate on California or Oregon. For all I know, they lied to me about everything. Maybe they lied to him as well?? If you are out there son, please just let me know you are okay. I have loved you everyday of your life. My whole family would love to know too, as everyone is worried about you. You have a younger half-sister and brother who would both love to meet you! If ANYONE can tell me what direction to go in, I would GREATLY appreciate it! Thanks for reading!