Have you contacted Dell* to see if they can provide you any possible driver updates on their side. Intel recommends that you contact your computer manufacturer first. Our latest drivers found in our Download Center are generic and may not be compatible to your system. In the meantime, here are some tips that might help you resolve this issue:
1 - Disable the Power Saving Functions - turning off the option may prevent unexpected disconnection, sudden connection-speed-drop issues.
2 - Set the adapter to work at its maximum performance - Go to Control Panel >> Hardware and Sounds >> Power Option >> Set the High Performance and apply to default settings. Check the Change Plan Settings >> Change Advanced Power Settings >> Wireless Adapter Settings >> Power Saving Mode and from there, make sure both On Battery and Plugged in are set to Maximum Performance.
3 - make sure your router/Modem is running the latest firmware as well.
Please, also check these links below as they may also help you resolve this issue:
thank you for your reply. I have tried driver updates, but I used Intel drivers, and it did not help. I tried to install Dell drivers, but compatibility error was returned right after I ran setup. In any case, I have noticed, that Dell installer unpacked Intel driver update tool, so probably the same thing would have been installed.
What confused me the most was that wifi card was disabled even in BIOS, so thought that it was not a software issue.
So far, it disabled again yesterday, but then appeared as usual. I'll try to contact Dell for driver updates; however at their forum there are many people complaining about similar things.
it would be great to see some kind of error log for this wifi card, so that I could diagnose the cause of that switching off behavior.
regarding power saving options - in my version there are no power settings for wifi adapter (there is display, battery, etc, only)
If the card cannot be detected to the BIOS level, we recommend that you contact your OEM ( Original Equipment Manufacturer) first for further assistance.
Check with them for a possible BIOS update.