Hi,

Please download the Intel wireless card driver from the Intel website to check if it fixes the issue. Check for the exact driver by referring to the operating system installed.

http://intel.ly/1J4iGpw

Please let me know if this helps.

I downloaded and installed the latest drivers from the link you provided, but it didn't work.

I tried disabling various startup programs and found that it is the QuickSet which is causing problem. As soon as QuickSet is loaded at startup, wifi and bluetooth both disappear. When I have stopped QuickSet from startup, it works fine. 

But QuickSet is essential for different battery modes I think, so we need it to work. (Wifi and Bluetooth disappear again in I launch the battery settings: "Desktop mode battery charge" and "Dell Extended Battery life options" settings. Since QuickSet is not running, these settings are not enforced. 

I downloaded latest QuickSet version from the driver download page for my laptop model, but still same issue.
I uninstalled and installed QuickSet again opting out the Radio features, but the issue remains. 

Hi,

I would suggest you to enable the Wireless in the quickset application to check if it’s disabling the WIFI once installed.