Dell :: Wireless 1704 802.11 B/g/n Remains On When Connect Via UTP

My BT Home Hub Router needs to be reset regulary when I unplug my wired connection and change to wireless 1704 on a 3 month old Inspiron Laptop (i5, 8Mb).

I assumed that the wireless connection would be disconnected when I connect to the wired connected. And then when I disconnect the wired connection (when I move to another room), I assumed that the wireless connection would automatically connect.  If I manually turn off the 1704 wireless adapter (Function F2) and just leave the laptop connected to the wired UTP connection, then then router is fine - but I dont have a mobile device. I have just re-ordered the connections so that the Local Area Connection (Realtek) is the first in the list and then the(Local Area connection 2 (Broadcom virtual, I dont know what this is) then the WIreless Dell 1704 b/g/n (Broadcom)

I can not find how to disconnect the wireless adapter automatically when I connect to UTP.  I know that I can switch off the manually by Function F2, but would prefer not to. Would this prvide the solution, and how do I do it?

One23 i5 2010.  XPS i5 2011.  And an old Carrera PC