This caller identifies himself as working for Microsoft and that my computer has a problem. He has an accent that is non-American. I've told him repeatedly that my computer is fine & to quit calling me. He continues to call and call and call for days on end. I have reported him to the Do Not Call Registry as well as the FTC and also to my phone company.
As of 9 AM, 6/18/2017, 55 calls from this number in the past week. We fortunately purchased a call blocker recently, so only the first one actually rang. I reported it to the totally useless Do Not Call registry too.