The Windows API is so broad, so deep and so functional that most ISVs (independent software vendors) would be crazy not to use it. And it is so deeply embedded in the source code of many Windows apps that there is a huge switching cost to using a different operating system, instead. It is this switching cost that has given the customers the patience to stick with Windows through all our mistakes, our buggy drivers, our high TCO (total cost of ownership), our lack of a sexy vision, at times, and many other difficulties. Customers constantly evaluate other desktop platforms, (but) it would be so much work to move over that they hope we just improve Windows rather than force them to move... In short, without this exclusive franchise, called the Windows API, we would have been dead a long time ago.
Vista sux
offtopic: LOL I had GeForce 4 MX on my old PC
Well since i got my new PC I installed both Vista and XP and guess what? XP is running like a bullet (event with custom WindowBlinds themes) while Vista takes like 5 min to start!!! (2GB ram, AMD 64 x2 4800+, ATI Radeon x1650)
I recently installed Ubuntu Linux and when I saw all those effects running with so less resource consuming (even less than XP) I instantly deleted Vista. But i keep XP for games ;)