How does apple’s differentiation strategy reflect its vision?

Apple Case Study 2 

Read on 4&5 the hbr book and the apple case to answer the following questions below:
4.Building Your Company’s Vision (Book) By James C. Collins; Jerry I. Porras
5. Reinventing Your Business Model (Book) By Mark W. Johnson; Clayton M. Christensen; Henning Kagermann Business Strategy
Apple Case: DifferentiationAssignment Questions

1. What were Apple’s major competitive advantages? Has Steve Jobs finally solved Apple’s long-standing problems with respect to the Macintosh business?
2. How does Apple’s differentiation strategy reflect its vision?
3. Why can’t Apple use the same strategy as other PC manufacturers, such as Dell and Lenovo?