Cannot set up iPhone 4S personal hotspot with Toshiba 940.

I have connected my Toshiba Tecra 940 Windows 7 to iPhone 4S via USB cable and the laptop recognizes the iPhone. Within the iPhone settings, I turn on personal hotspot (previously I have set up a compliant password for this feature). When I go into the Intel wireless proset connection program on the Toshiba, I do not see my iPhone in the display of network devices to select. even when I go into the Windows network connection and sharing Center. I do not see the iPhone listed. Any article or technical paper on this that you know of would be appreciated. Thank you. Carl