To dream about a memory suggests that you are ready to rid yourself of your old ways and undergo a transformation. You are ready for a new outlook in life. Recalling a memory in your dream may also be less of a shock then if you had recalled the memory in your waken state. Alternatively, the dream indicates that you have learned from your past experiences.
To dream that your memory is getting or has been erased means that you must let go of the past in order to move forward with your life. You are stuck in an unhealthy cycle.