As its name implies, Vista Start Menu Emulator installs an emulator that simulates the Windows Vista Start Menu.
Since it's an emulator, you can place it wherever you like on your screen. That way, it can live peacefully alongside the traditional Windows XP Start Menu.
In addition to providing direct accesses to your most frequently-used locations, Vista Start Menu Emulator gives you a more convenient way to display your program folders. Clicking any one of them will expand it so that you may see its contents.