System:  Alienware M17XR3 with DW1501 Wireless-N WLAN Half Mini Internal Wireless Card. Running Windows 7 Home Premium.

Wireless connection has worked fine for years.  Yesterday, with no program changes, a red X appears over the network connection icon and it states:  "Not connected.  No connections are available".  This while plugged in to charger with power profile set to performance.

It will connect to the internet via ethernet cable.  Toggling wifi on/off with the media control button changes nothing.  The network is available as two other computers connect to it without problems, one at 2.4GHz and one at 5GHz (dual band router).

Upgraded router firmware.  Installed new wireless card driver.  No effect.  Wireless is activated in BIOS.  Device manager says all devices operating without problems.  Windows network troubleshooter can not identify the problem.  Alien Autopsy finds no available network.

Uninstalled DW1501 and driver and reinstalled.  No joy.  Uninstalled again and tried to install a USB wireless card (Linksys AE1000).  Linksys install CD could not install, says wireless control may not be Windows, which it requires...   Downloaded Linksys driver for AE1000, installed thru Device Mgr, shows up working in device mgr but still no wireless connection.

It appears that neither my internal adapter nor a USB adapter can receive the wireless signal that is indeed present.  Any suggestions?  I have run out of ideas.