Windows 2000 is an enhanced version of NT, not an enhanced version of Windows 98 or Windows 95. If you are a Win9x user and a game player, you could run your games in a pure DOS environment by rebooting Win9x to load a pure DOS environment. This is not available under Windows NT or Windows 2000. DOS compatibility is the same in Windows NT and Windows 2000. There is no DOS code in either. What you have available is a DOS shell which emulates the DOS operating system. As an emulator it will be slower than real DOS. As an emulator, the compatibility is not perfect. There are DOS programs that will run in a real DOS but which will fail in the Windows NT or Windows 2000 DOS shell. Luckily Windows NT and Windows 2000 support dual boot such that you can have your cake and eat it too: run either Win9x or Windows 2000 at your choice. Be sure to install Win9x first and then install Windows 2000 into a separate partition.