After more expermentation I find that the problem occurs every time the computer goes to sleep.
If I reboot WI-Di works flawlessly.
As I mentioned previously, "Allow the computer to turn off power to this device" box is already unchecked.
Is this normal that one must reboot the computer to restore functionality once the computer entered nthe sleep mode and thereby enable the Intel Wi-Di function to operate?
Or is there a way to set it up so that Wi-Di will still operate after the pc has taken a nap (without a reboot)?