The marginal cost of selling software is $.00 pretty much. So MSFT operates on a what-the-market-can-bear approach, not a costco-style mark-up-everything-10-percent appraoch.

You are implying there is some relation between the price of Windows and the amount of work that goes into it. Given the size of their war chest, one could argue that they already charge much more than their software costs to produce.