Screen Navigation and Usability

Using your favorite search engine, perform a web search on the terms "software usability and navigation". In a written report, first provide a definition for usability. Describe at least three or four methods or principles for achieving good design and effective navigation for screens in a software application or website. 

Apply and compare how usability factors affect your own enjoyment and ability to learn and use a specific type of computer software or website. Be sure to fully explain the principles that you studied in paragraph form; do not provide just a list or outline.