Delete all of the existing "profiles". Go into the Network and Sharing Centre and click the link at the left to "Manage Wireless Networks". In the window that opens, highlight each item in turn and click the "Remove" button.
With no items remaining, close the window and use the network icon in the Notification Area (beside the clock) to "Connect to a network". Then try to connect to your Wanadoo/Orange network again. The network adapter should no longer automatically try to connect to the Belkin network, although it will continue to be shown as an available network if it's running.