My co-worker came to me with his Dell Inspiron 35xxx laptop (Haswell i3). Windows 10. He said the other day the Wifi just turned off and he couldn't figure out how to get it working. There is no physical WiFi switch, you can toggle airplane mode on/off using Fn+F2. He later plugged the laptop in via ethernet, which worked fine for a couple days, then that too stopped working.
I brought it home last night figuring it was an easy fix. So I uninstalled all network drivers and reinstalled them and found some odd things:
1) Even after installing the ethernet driver, no ethernet device shows up in the network adapters list or device manager. Can't get internet connection via ethernet.
2) WiFi still stays off regardless of Fn+F2 toggles or flipping the WiFi "switch" in Windows 10 settings. Flipping the WiFi switch in Windows 10 settings shows wifi seemingly turning on (initiating), then after a few seconds the switch just moves itself back to the off position. The Wifi device shows in network adapters, but nothing I could think to try would get it to turn on. There is a greyed out wifi icon in the taskbar with a red X saying something to the effect of "Not Connected, No WiFi signal"
I'm kinda stumped. My typical approach in these situations is to reformat. But I figured I'd check with the gerbil collective for any other device before taking these extreme measures.