DELL Inspiron 1750, Windows 7, Wireless problem

The connection from WLTray occurs at boot then drops immediately and at the top is says "Not connected" but  I am actually connected and able to get on the Internet, etc.  The problem here is under the Network and Sharing enter, I get a big red X here myu router is supposed to be and I am unable to view or manage the connection.

The problem is definitely not the router because I have several other machines running Win 7 and Vista and work fine.    I have spend a lot of time upgrading drivers and changing setting but still no joy.    Does anyone have ideas on what to try?   I would like to say this is a bug with Win 7 or the drivers, but I have other machines with the WLAN 1397 and same config that work okay.

Regards,

-map