I had the same problem and tried everything! I finally absent-mindedly mentioned it to a woman from Sprint. She gave me the ANSWER! It was my free music download app! I deleted it and the pop-ups immediately stopped. Just to make sure, I reinstalled the app and they started all over again! I just found one called MP3 Music that has a multi-colored, round icon with a double music note inside of it...it has not caused these issues like the last app. I'll post a pic.