Newtorks not detected by New WiFi Adapter

Started to upgrade a Dell Vostro i7-86o with a Wifi Adaptor.
Operating System is Windows 7 Professional 64 bit.

The adapter installed Ok and in Properties it says "This Device is working properly", but it does not detect any wireless networks.

To confirm that the Adaptor was not faulty I swapped it with TP Link TL-WN881ND from another computer. The original EDIMAX 7612 now works fine in the other PC.

The problem is obviously in the Dell. One of the myraid setting in Win 7 Professional.

So far I have restarted umpteen times, downloaded Windows updates, disabled and enabled the LAN and Uninstalled and Installed the WiFi.

Also had to set WLan to Auto start. Turned Windows Firewall Off. Turned Zone Alarm off.
Tried pressing FN8. Tried changing adapter settings etc.

I have also tried in Command window: netsh int ip reset

While trying all that, on several occasions used Network & Sharing Centre, and then Change Adaptor settings. It opens a status window which shows activity.

Packets are consistently being sent but Nil received.

Now run out of fixes to try! Any advice much appreciated.