Can't get rid of "artificial" wifi network

Yesterday, in my other blog, I described how I set up a very nice system to share a wired connection wirelessly when no wifi is available from the router.
This works fine. However, I just can't get rid of the artificial wifi network I set up on the Dell Desktop with the aid of a Belkin usb wireless receiver.
I've tried the following to stop it showing up in Network Manager:
1. Gconf Editor (Systems>>Networking>>Wireless>>Networks
However, only the network I was using showed up, not the phantom network that I'm trying to get rid of.
2. Right-click on nm applet and Edit Connections>>Wireless Tab and delete the unwanted network. If it doesn't show up here, just left-click on nm applet and click on the network. Now it should show up under the Wireless tab.
3. Plug out Belkin wireless receiver
4. Reboot

For some time after repeatedly trying each of these, the unwanted network still showed up when I left-clicked on the applet.
Then, all of a sudden, it disappeared. Something else I just don't understand.