I know my daughters fathers name and need help finding him were do I start?

[Nicky]

U.S. census won't help you since the information isn't released to the public until after 72 years have elapsed. Do you know where he's from? Maybe do a local phone search in his hometown for people with the same last name and make a few calls to inquire if they are related and in touch (or know someone who might be). The only other option would be for you to hire someone to look for him going back through various public records from the time you last saw him until now. You can do a few searches online, such as SS death index if you have any of the pertinent information (DOB, birthplace, etc) to see if he's still around, try some of the online social groups (facebook, myspace, etc) to see if you can locate him in that manner or locate some of his personal friends from the time when you knew him to see if they can help you.