I need a VERY clear and easy to follow explanation

1. You plan to develop a new software system that will make all other systems obsolete. In planning for this operating system, you need to estimate the percentage of computers that use Windows. a) Assume that nothing is known about the percentage of computers that use Windows, find the number of people that must be surveyed in order to be 98% confident that your estimate will have an error by no more than one percentage point. b) Find the number of people that must be surveyed in order to be 98% confident that your estimate will have an error by no more than one percentage point given that 76.56% of computers in the USA use Windows