My mom wants to find her parents names. She asked her adoption agency but they cant give out the information, how can she get their details?
Might be best to use Ancestry.com or My Heritage.com to help find relatives. Your mom most likely had a closed adoption (I know mine was closed) and so the records are sealed . You would need a court order to open them to find out this information. Its not an easy thing to do and I wish your mom luck in finding out information.
In what state was she adopted? Some states have opened adoption records, and it would be as easy as requesting her original birth certificate. If she lives in a closed records state, she might consider submitting her DNA to ancestry.com or 23andme.com. I found my previously unfindable original father through cousin matches at ancestry.com.
She hires an investigator who looks at all available sources of info.
She can try ancestry.com