How to Disable the Original WiFi adapter
If your laptop has built-in WiFi but you add a new adapter that connects through the PC Card adapter or a USB port, you will need to remove or disable Windows drivers for the original unit. You should also make sure that you turn off the switch for the built-in unit to save battery power and to avoid the possibility of interference.
To disable the drivers, do this:
Go to the Windows Control Panel.
The System Properties panel appears.
Choose the Hardware tab.The Hardware options appear.
Choose Device Manager.
Click the + next to Network Adapters.The hardware managed there appears in a list.
Double-click the wireless component.
Its properties are displayed.
Click the Device Usage drop-down arrow.
Select Do Not Use This Device (Disable).
This instructs Windows not to use the drivers associated with it.