XPS 8700 Internet stopped working after windows update 1709

Are there any LEDs lit near the Ethernet connector on back of the PC?

Did you look in BIOS setup (reboot and immediately press F2) to make sure the onboard NIC is still Enabled?

Is the NIC still listed in Device Manager or did it disappear? Are there any "unknown" devices listed in Device Manager?

Have you tried uninstalling the NIC driver then reinstalling/updating the Intel chipset and AMT HECI drivers, rebooting and then install the NIC driver again? Unless the chipsets are correctly installed, other drivers may not install or may not work.

There's a new thread in the XPS forum about a similar issue with the XPS 8700, but that one is running Win 7, so it may or not be the same problem...

Are there any LEDs lit near the Ethernet connector on back of the PC?

Yes. I unplugged my cable and attached it to another PC. It works fine. I took their cable and attached it to mine. No internet. The lights work. I reset the router too. No luck.

Did you look in BIOS setup (reboot and immediately press F2) to make sure the onboard NIC is still Enabled?

Yes. I also toggled LAN boot ROM in the BIOS advanced settings as some other user suggested. That didn't help either.

Is the NIC still listed in Device Manager or did it disappear? Are there any "unknown" devices listed in Device Manager?

Yes. 

https://imgur.com/a/8MdKf

Have you tried uninstalling the NIC driver then reinstalling/updating the Intel chipset and AMT HECI drivers, rebooting and then install the NIC driver again? Unless the chipsets are correctly installed, other drivers may not install or may not work.

Yes, I uninstalled and reinstalled the Realtek drivers to the latest and the version before. But that didn't help. I didn't try uninstalling/reinstalling the chipset drivers. The drivers from Dell's site seem quite old for the 8700's chipset. Anyway, I tried reinstalling them both. No luck.

All I am left now is to reinstall Windows 10 from an ISO image that I found on Microsoft's site.

I posted a response here, but it seems to have disappeared. Let's see if I remember what I said...

Did you look in Device Manager to see if the RealTek is still enabled?

Did you open the Network and Sharing page in Windows and configure your network, making sure it's set to use the RealTek and not one of the virtual adapters listed in Device Manager?

If you only ever got drivers from Dell's site, the "old" chipsets should work. If one of the current chipsets is newer than the one you're trying to install, you'll get a warning and you can just abort the installation.

If all else fails, you can try to Refresh the Win 10 installation. You shouldn't lose your files with a Refresh, but back them up first on external media. You will have to reinstall your apps.

 You could also try booting from a USB with that MS Win 10 file and doing a Repair, not a clean installation...

Did you open the Network and Sharing page in Windows and configure your network, making sure it's set to use the RealTek and not one of the virtual adapters listed in Device Manager?

I disabled the virtual ethernet (which is set to default switch) and the WiFi adapter. The only network that is enabled is the RealTek.

Is that what you meant?

I ran the troubleshooter many times. It wasn't useful. 

Advanced settings in the network and sharing page does not even show the Realtek as an option. How do I configure it to use it (if that is the issue)?

Yes, but did you make sure your Network & Sharing page is correctly configured to use Realtek and not one of the (disabled) virtuals?

Have you tried running the Win 10 Network troubleshooter?

OK I figured that part out, but when I tried to add an access point in the "set up new router or access point", it didn't populate it with anything.

I went ahead and reinstalled Windows 10 from the ISO image on Microsoft. Even that didn't work. I am clueless as to what to do next.

BTW: If you reinstalled Win 10 from the  MS ISO file, did you install all the drivers from Dell's site too, including chipsets and Realtek drivers after the OS?

Is the RealTek hardwired to the router? If the router has more than one Ethernet port, have you tried a different one?

I guess it's possible either the onboard NIC or the router failed. Can another PC connect to the router via this same Ethernet cable and then connect to the internet?  

If the router is working with another PC, your options might be setting the XPS 8700 up on a WiFi network, assuming you have an add-in internal WiFi card, or maybe getting a USB>Ethernet dongle which plugs into to a USB port on the PC and to the Ethernet cable to the router.

Is the RealTek hardwired to the router? If the router has more than one Ethernet port, have you tried a different one?

I guess it's possible either the onboard NIC or the router failed. Can another PC connect to the router via this same Ethernet cable and then connect to the internet?  

Yes it is. As I mentioned, I connected the Ethernet cable from my PC to another one and that went online fine. I swapped the cable from that PC, and I still didn't have any internet.

If the router is working with another PC, your options might be setting the XPS 8700 up on a WiFi network, assuming you have an add-in internal WiFi card, or maybe getting a USB>Ethernet dongle which plugs into to a USB port on the PC and to the Ethernet cable to the router.

The PC has an internal WiFi card, and even that doesn't see the internet.

BTW: If you reinstalled Win 10 from the  MS ISO file, did you install all the drivers from Dell's site too, including chipsets and Realtek drivers after the OS?

Just tried that. No luck.

:Yes: :Yes:

Thanks for posting the solution because it might help somebody else.