• Go to Control Panel.
• Choose Administrative Tools.
• Select Services. A two-pane window comes up.
• In the right-hand pane, scroll down and click Wireless Zero Configuration.
• Click Stop the Service. A progress bar may come up briefly.
• Click Start the Service. Again, a progress bar may come up.
• Close the Services window. At this point, Fleishman said, the connection should come back.
I suspect it's a problem with certain machine/PC card combinations.