I wanted to get back to you. I found Harry C. Windsor in the 1930 Oregon census, Multnomah Co., city of Portland, e.d. 26-92, sheet 5A, p. 48. He was 67 years old, born in Iowa. According to the census he was a widow, and lived in a rooming house. The census also states his father as born in New York and mother in Canada. He occupation was listed as laborer doing odd jobs.
I also found him in the Oregon Death Index: Harry Windsor, d. 27 January 1936, at Portland, Multnomah Co. Oregon. Wife's name was Mary. Certificate no. 332.
Perhaps the death certificate gives the name of his parents.
I have not been able to find Harry Cornelius Windsor in any other census. You said in your letter you had found him in the 1910 census. Does that census state the birthplace of his parents, if so where does it say they were born?