When in the day and how often are these accidents. The answers may hold a clue as to why this is happening.
Does she free feed, how much freedom does she have in the home, was she ever trained or has she always had accidents. These are just a few questions.
Pick up a black light and check your home to see if there are still spots. The area will glow. When you use a steam cleaner to clean up you sometimes make a small spot much larger and miss some of it in the process.
You may need to back up and start from scratch as if she were an 8 wk old puppy.