Alienware Aurora R4 Wifi Not Working?!?

My Aurora R4 has been working like a dream since I purchased it 4 months or more ago until now.  When I boot my computer up and the Windows 7 desktop appears, the wifi logo in the desktop tray below appears then searches for my internet connection and then disappears showing a hard wired ethernet logo with a red cross indicating no connection.  I have checked device manager and the computer does not even show a wireless card present at all?  I have had to put up with this for a month or more now as I have been really busy to sort this out but I finally phoned Dell support who suggested re-installing the drivers, which I did and made no difference at all, the same problem exists.  I have read some forums of people with the same problems and Dell have sending numerous engineers to people and can't fix the problem but make the system perform slower?

Does anyone else have the same or had the same problem that can shed some light on this matter for me please?