My company has six identical Dell Latitude E4200
computers. all are running preinstalled Windows 7 x64. I've installed updates and the same software on each and distributed all but one of them to users.
The first five will not automatically connect to any wireless network. The sixth will automatically connect to the office wireless network (WPA-2) but will not automatically connect to another wireless network (WEP) when I tested it. If I export the office wireless network connection settings of the sixth to a USB key and then import it on one of the first five, that one then automatically connects. So it seems to be some property of the connection.
On all six:
The WLAN Auto Config service is set to Automatic and is started.
In the connection properties, "Connect automatically when this network is in range" is checked. I tried checking "Connect even if the network is not broadcasting its name".
The logged-in user is a local administrator.