Disappearing Wireless adapter

I had this happen to me about 2months ago. Dell 5480. Only with my issue, I have NO connections available. As in, no Local area, no wifi. Nothing. They are visible under hidden devices, but they are disabled, with no way to enable them it's greyed out. I've tried installing all the Internet drivers (Intel wireless adapter, LAN adapter, etc). They will install. But still after reboot nothing. I've deleted adapters, reinstalled. Searched the bios. Searched event viewer and registery to locate an event that may have caused this. Deleted excess software. Deleted recent windows updates. I did check Services and Default apps. But, I don't know 100% which services and default apps should be enabled or disabled. From what I saw, they looked okay. But that might be something someone with more knowledge could maybe provide for us please. I also did notice my Bluetooth adapter staying installed. I'm going to try and Uninstall and disable in bios. see if that helps at all. Dell or someone, please help us!!! Thank you.

So I noticed my wifi adapters power state mappings for S1 and S2 show as undefined, and I suspect that this is part of the issue.

The Bluetooth adapter which is the same piece of hardware and never has any issues has the same power states defined as D3.

I learned how to investigate power configurations in the command prompt window.

When querying the system about which devices support S1, S2, and S3 (the different sleep levels), the wireless adapter is not present on the S1 or S2 list (although literally every single other device on the computer seems to be listed here) but it is on the S3 list.

To me this implies that the system loses track of the adapter when entering the S1 and S2 phases and that's why we're not able to see it again until reboot.

So it looks like my laptop doesnt use S1 or S2 anyways

how is this even an acceptable answer? Factory restore to fix a network connection?  If Dell sold cars would we be buying a new car every time it needed an oil change? 

Your solution is 100% unacceptable

Hello, were you able to solve your problem? My wireless adapter is also not being recognized. I already bought a new one. But it still doesnt work. Funny thing is, Bluetooth is working just fine. Thanks

My 7375 randomly will boot up without wifi (device manager will not list the device, yet the bluetooth device is always listed).  I dual-boot, and If it doesn't work in windows and I reboot into Linux, it doesn't work there either.  The best thing I've found is to boot f12 >'device configuration' and wait until the fan kicks in, then exit and let it boot up.  Most of the time this fixes it, but its a huge PITA.  I sent my laptop back to dell for repair a month or so ago.  I thought it was 'fixed' for about 2 days.  They replaced the wifi card and io board.  This seems like it's a bios power related issue to me.  Especially since it behaves the same regardless of OS.  It happens mostly when cold starting the machine after it's been unused for hours.  I have, per dell's hoop jumping, reinstalled Windows a few times, ran diagnostics, etc.  I've followed troubleshooting advice from a myriad of forums.  I've disabled the option for windows to control the power to the wifi card.  I've replaced the wireless card with an ac9260.  I've swapped wireless cards a few times.  I've messed with a few options in the bios f12 > 'device configuration' that don't really make sense … AMD > 'WLAN/WIFI Power enable' by default is 'disabled'.  I've set it to all options 'disabled/enabled/manual' and nothing seems to consistently get it to work properly.  This is both the best and the worst laptop I've ever owned.  If there are any other suggestions that haven't been mentioned, I'll try whatever.  I hate the awesome laptop.

Very helpful! Thanks.

Got the same exact issue, got tired going through steps to try, even ruined my personal data by formatting laptop and still issue wasn't fixed. Tried registry editor and network reset to no avail.

** SOlution for me was to simply look up a youtube video on getting to the wlan card, basically googile "e5440 wifi card removal" and play the first clip. 

I undid the 5 screws at the bottom, then the one directly on the nic card, took it out, back in snug, and tightened everything down. voila and it  worked. wasn't too difficult, was simply a lazy  and reluctant to get the precision screwdrivers and tear things up.

Hope it helps at least one other person.

This did not work for me. I deleted the wireless network adaptor and reloaded it and restarted my computer but it didn't work. 

I then reset the laptop to factory settings and it still is not showing any wireless adaptor.

Now I have no choice but to take this one year old laptop to a repair shop. 

I have had a lot of inexpensive toshiba computers in my life and NONE of them did what this $1200.00 Dell is doing right now. I will NEVER buy another Dell laptop again and I will tell everyone I know what a POS this computer is. 

resolved the problem by turning off fast startup in power options. your post hinted towards the problem.

Fast startup (reduced hibernation file)

Fast startup is a type of shutdown that uses a hibernation file to speed up the subsequent boot. During this type of shutdown, the user is logged off before the hibernation file is created. Fast startup allows for a smaller hibernation file, more appropriate for systems with less storage capabilities. For more info, see Hibernation file types.

When using fast startup, the system appears to the user as though a full shutdown (S5) has occurred, even though the system has actually gone through S4. This includes how the system responds to device wake alarms.

Fast startup logs off user sessions, but the contents of kernel (session 0) are written to hard disk. This enables faster boot.

To programmatically initiate a fast startup-style shutdown, call the InitiateShutdown function with the SHUTDOWN_HYBRID flag or the ExitWindowsEx function with the EWX_HYBRID_SHUTDOWN flag.