Basis the "What's This" explanation of the choices under Audio device driver:
Option 1: "Do not use audio features on this device" :
Prevents your programs from using this device driver. The driver remains on your disk, but it is no longer loaded into memory when you start your computer.
Option 2: "Do not map through this device"
Prevents your programs from using this device driver. Unless one of your programs specifically requests it, this device will not be used".
My interpretation (and I do not play a microsoft vista design engineer in real life or on TV):
Selecting 1 renders the device generically unavailable. However by selecting 2 as well a program can force mounting of the driver.
Option 1: "Do not use audio features on this device" :
Prevents your programs from using this device driver. The driver remains on your disk, but it is no longer loaded into memory when you start your computer.
Option 2: "Do not map through this device"
Prevents your programs from using this device driver. Unless one of your programs specifically requests it, this device will not be used".
My interpretation (and I do not play a microsoft vista design engineer in real life or on TV):
Selecting 1 renders the device generically unavailable. However by selecting 2 as well a program can force mounting of the driver.