To help diagnose network-related problems, a "Network Diagnostic" mode is available.  To enable or disable it:

1. Click on the "Hardware Profiles" page.
2. Hold down the "Shift" key and click on the "Exit" button.  Select "No" in the confirmation window.
3. Double-click on the window background behind the tab set, just inside the window borders.
4. Click the "Options" page.
5. Click the "Restore Net. Connections at Startup" or "Restore Network Connections" option.  (You may click it again to return it to its previous state).
6. Click the "Allow Net. Connection Substitution" or "Use Alternate Network Connections" option. (You may click it again to return it to its previous state).
7. You will see a confirmation window that Network Diagnostic mode has been enabled or disabled.