The study explored blind users' mental models and strategies in coping with the Windows environment and investigated the relationship between users' mental models and usability problems they face when using a screen reader. The study found that blind users possess a functional or structural mental model or a combination thereof. Blind users also have a rich and highly procedural strategy for coping with a new Windows environment and application. Users' established mental models developed from using a familiar screen reader were found to contribute to problems in using a new screen reader.