Just unboxed your new gaming PC, plugged in the Ethernet cable, and got… nothing. No internet, a spinning circle, or a dreaded “No Internet, Secured” or “Unidentified Network” message where a gigabit connection should be. The port light might be dark, flashing amber instead of green, or Windows shows a globe icon with a slash through it even though Wi-Fi works fine on your phone.
This is one of the most common out-of-box problems on new prebuilts and custom builds, and it is almost always fixable in under 15 minutes without replacing hardware. Do not assume the motherboard is defective or immediately buy a USB adapter. Work through the checks below in order, from the physical cable to Windows settings, and you will isolate whether the issue is a loose connection, a disabled adapter, or a missing driver. As of early 2026, most new gaming motherboards ship with 2.5GbE controllers that need specific drivers to function.
Likely Causes
| Cause | How to confirm | Fix difficulty |
|---|---|---|
| Loose, faulty, or wrong-port Ethernet cable | No click when inserting, no LEDs on PC port or router port, cable works on another device | Easy |
| Ethernet adapter disabled in Windows | Settings > Network & internet > Advanced network settings shows Ethernet as Disabled | Easy |
| Missing, generic, or outdated LAN driver | Device Manager > Network adapters shows yellow exclamation, “Ethernet Controller,” or only Wi-Fi adapter | Easy |
| LAN controller disabled in BIOS/UEFI | Ethernet does not appear in Device Manager at all even after driver install | Moderate |
| Power management or Fast Startup interfering | Ethernet works after restart but not after shutdown, or drops after sleep | Easy |
| Corrupted IP stack / DHCP failure | ipconfig shows 169.254.x.x address, status says “Unidentified Network – No Internet” | Moderate |
Fix 1: Check the Physical Cable and Port
What causes it
New cases often have stiff I/O shields, dust plugs in the RJ45 jack, or tight cable routing that prevents the connector from seating fully. A damaged cable, a cable plugged into the wrong wall jack, or a router port that has not been activated will also give you a dead connection with no link lights.
How to check
Look at both ends of the cable. On the back of your PC, the Ethernet port should have two small LEDs. On most gaming boards, steady green or white indicates link and flashing amber indicates activity. No light at all means no physical link. Unplug and reinsert the cable until you hear a clear click from the retention clip. Inspect the clip itself – if it is broken, the cable will slip out. Check the router or switch end and confirm that port’s LED is also lit. If you have a modem/router combo, make sure you are in a LAN port, not the yellow WAN port.
What to do
1. Power off the PC, remove any plastic dust cover from the RJ45 port, then firmly reseat the cable.
2. Try a different Cat5e or Cat6 cable that you know works, ideally one that is currently providing internet to another device.
3. Try a different LAN port on your router. Unplug the router power for 30 seconds, then plug it back in and wait for all status lights to stabilize before testing.
4. If you use a wall Ethernet jack, bypass it and connect the PC directly to the router with a short cable to rule out in-wall wiring.
How to undo it
Simply reconnect your original cable and port. No software changes are made, so there is nothing to revert in Windows.
Fix 2: Enable the Ethernet Adapter in Windows
What causes it
Windows can ship with the wired adapter disabled by default, especially if Wi-Fi was set up first during the initial out-of-box experience. Game-first utilities like Armoury Crate or MSI Center can also toggle the adapter off to prioritize wireless.
How to check
Press Windows + I to open Settings, then go to Network & internet > Advanced network settings. Under Network adapters, look for Ethernet. If it says Disabled and is grayed out, this is the culprit. Alternatively, press Windows + R, type ncpa.cpl, and press Enter. The Control Panel Network Connections window will show all adapters. A red X or gray icon on Ethernet means it is disabled or disconnected.
What to do
1. In Advanced network settings, click Enable next to Ethernet and wait 10 seconds for it to show Connected.
2. In the ncpa.cpl window, right-click Ethernet and choose Enable if available.
3. Right-click Ethernet > Status and confirm Speed reads 1000 Mbps or 2500 Mbps. If it says 0 Mbps, the cable is still not linking – return to Fix 1.
4. Click Details in that Status window and verify DHCP Enabled says Yes.
How to undo it
To disable again, return to Settings > Network & internet > Advanced network settings and click Disable next to Ethernet, or right-click Ethernet in ncpa.cpl and choose Disable.
Fix 3: Install or Reinstall the Correct LAN Driver
What causes it
Fresh Windows installs often load a generic Microsoft driver that cannot drive the Intel I225-V/I226-V, Realtek RTL8125/RTL8126, or Killer E3100 2.5GbE controllers used on most current gaming motherboards. Without the vendor driver, the adapter appears as “Ethernet Controller” with a yellow triangle or does not appear at all.
How to check
Press Windows + X and select Device Manager. Expand Network adapters. If you see “Ethernet Controller,” “Unknown device,” or a yellow exclamation mark, the driver is missing. Right-click Ethernet Controller > Properties > Details tab > Property: Hardware Ids. Note the VEN and DEV values, for example VEN_10EC for Realtek or VEN_8086 for Intel. That tells you the chipset even without a driver. Also check that no driver is pending under Other devices.
What to do
1. On another device with internet, go to your motherboard support page. Search by exact model printed on the board or box, for example “ROG STRIX B650-A GAMING WIFI” or “MSI MAG Z790 Tomahawk.”
2. Download the LAN driver for Windows 11 64-bit to a USB drive. Do not use a generic driver pack.
3. On the new PC, run the installer as administrator. For Intel, it is typically named Wired_driver_xx.x.x.x.exe. For Realtek, it is an AutoInstall package that places files in C:\Program Files\Realtek\NicDrv_8169.
4. When prompted, choose to install the driver and reboot. After reboot, Device Manager should list “Intel(R) Ethernet Controller” or “Realtek Gaming 2.5GbE Family Controller” without warnings.
5. If Windows already had a driver but it was faulty, right-click the adapter in Device Manager > Uninstall device > check “Attempt to remove the driver for this device” > Uninstall, then reinstall the downloaded package and reboot.
How to undo it
In Device Manager, right-click the Ethernet adapter > Properties > Driver tab > Roll Back Driver if the new driver performs worse. Or right-click > Uninstall device, then reboot and let Windows reinstall the previous Microsoft driver automatically.
Fix 4: Enable the LAN Controller in BIOS/UEFI
What causes it
Some prebuilts and custom motherboards ship with the onboard LAN controller disabled in BIOS to save power or because a Wi-Fi-first profile was applied. When disabled, the adapter will never appear in Windows regardless of drivers.
How to check
If Device Manager shows no Ethernet adapter at all after installing the correct driver, and Settings > Network & internet shows only Wi-Fi, the controller is likely disabled at the firmware level. The connection will also be absent from ncpa.cpl.
What to do
1. Shut down the PC fully, then power on and repeatedly tap Del or F2 during boot to enter UEFI Setup. On ASUS boards use Del, on MSI use Del, on Gigabyte use Del.
2. Navigate to Advanced > Onboard Devices Configuration or Settings > Advanced > Integrated Peripherals. Exact path varies by vendor.
3. Find options named “Onboard LAN Controller,” “Intel LAN Controller,” “Realtek LAN Controller,” or “LAN Option ROM” and set them to Enabled.
4. Press F10 to Save & Exit, confirm Yes, and let Windows boot. Re-check Device Manager for the adapter.
How to undo it
Re-enter BIOS/UEFI and set the same Onboard LAN Controller setting back to Disabled, then Save & Exit. This fully hides the port again.
Fix 5: Disable Power Saving and Fast Startup
What causes it
Windows Fast Startup and the adapter’s power management can prevent the Ethernet controller from waking properly after shutdown or sleep. The result is an adapter that says “Network cable unplugged” until you restart, or one that drops to 100 Mbps or disconnects after the PC sleeps.
How to check
In Device Manager, right-click your Ethernet adapter > Properties > Power Management tab. If “Allow the computer to turn off this device to save power” is checked, power saving is active. To check Fast Startup, go to Control Panel > Hardware and Sound > Power Options > Choose what the power buttons do. Click “Change settings that are currently unavailable” and see if “Turn on fast startup (recommended)” is checked.
What to do
1. In Device Manager > Ethernet adapter > Properties > Power Management, uncheck “Allow the computer to turn off this device to save power.”
2. Go to the Advanced tab, set “Energy Efficient Ethernet” to Disabled, “Green Ethernet” to Disabled if present, and “Wake on Magic Packet” to Enabled.
3. Open Control Panel > Hardware and Sound > Power Options > Choose what the power buttons do > Change settings that are currently unavailable, uncheck Turn on fast startup, and click Save changes.
4. Shut down completely, wait 10 seconds, then power on and test.
How to undo it
Re-check “Allow the computer to turn off this device to save power” on the Power Management tab, set Energy Efficient Ethernet back to Enabled, and re-enable Turn on fast startup in Power Options.
Fix 6: Reset the Network Stack and Force DHCP
What causes it
A corrupted Winsock, TCP/IP stack, or a stale DHCP lease can leave the adapter with a self-assigned 169.254.x.x address. Windows will show “Unidentified Network” and “No Internet” even though the link lights are on and the driver is correct.
How to check
Press Windows + R, type cmd, press Enter. Type ipconfig /all and press Enter. Find the Ethernet adapter section. If IPv4 Address starts with 169.254, DHCP Enabled is Yes but no DHCP Server is listed, or Default Gateway is blank, the PC is not getting an address from the router. Also check Settings > Network & internet > Ethernet > IP assignment. If it says Manual with blank fields, DHCP is off.
What to do
1. Open Command Prompt as administrator: Press Windows + S, type cmd, right-click Command Prompt > Run as administrator.
2. Run these commands one at a time, pressing Enter after each:
netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /renew
ipconfig /flushdns
3. Reboot the PC.
4. After reboot, go to Settings > Network & internet > Advanced network settings > Advanced sharing settings and confirm network profile is set to Private.
5. If ipconfig still shows 169.254.x.x, go to Settings > Network & internet > Ethernet, click Edit next to IP assignment, set it to Automatic (DHCP), and Save. Alternatively in ncpa.cpl, right-click Ethernet > Properties > Internet Protocol Version 4 (TCP/IPv4) > Properties > select “Obtain an IP address automatically” and “Obtain DNS server address automatically” > OK.
How to undo it
The reset commands cannot be directly undone, but you can restore a manual setup if you had one. Return to Settings > Network & internet > Ethernet > Edit IP assignment and set it back to Manual, re-entering your previous IP address, Subnet mask, Gateway, and DNS values.
Fix 7: Force Correct Speed and Duplex and Re-create the Adapter
What causes it
Auto-negotiation between a new 2.5GbE PC and an older 1GbE router or a long, low-quality cable can fail, leaving the port linking at 10 Mbps or not at all. A corrupted network profile can also keep the adapter in a failed state even after driver fixes.
How to check
In Device Manager, right-click Ethernet adapter > Properties > Advanced tab. Look for “Speed & Duplex” or “Connection Type.” If Value is set to Auto Negotiation but Status in ncpa.cpl > Ethernet Status shows Speed at 10 Mbps or 100 Mbps on a gigabit network, negotiation is unstable. Also run Settings > Network & internet > Advanced network settings > Network reset. If that page shows the adapter as having errors, a reset may help.
What to do
1. In Device Manager > Ethernet adapter > Properties > Advanced tab, select Speed & Duplex and set Value to “1.0 Gbps Full Duplex.” If your router supports 2.5 Gbps and you have a Cat5e or better cable under 100 meters, you can try “2.5 Gbps Full Duplex.” Click OK.
2. Unplug and replug the Ethernet cable and wait 15 seconds.
3. If it still fails, go to Settings > Network & internet > Advanced network settings > Network reset > Reset now. This removes and reinstalls all network adapters and sets networking components to default. Confirm Reset now and reboot.
4. After reboot, reconfigure Wi-Fi passwords as needed and test Ethernet first before enabling Wi-Fi.
How to undo it
Return to Device Manager > Advanced tab > Speed & Duplex and set Value back to Auto Negotiation, then click OK. The Network reset itself cannot be undone individually, but you can manually re-add any VPN or virtual adapters you previously used.
If Nothing Works
If the port LEDs never light with multiple known-good cables and router ports, try the PC on a completely different network, like a friend’s router or a direct connection to a laptop with Internet Connection Sharing. If it fails there too, the onboard controller may be defective. Check Device Manager > Ethernet adapter > Properties > General tab for error codes like Code 10 “This device cannot start” or Code 31. For a new prebuilt, contact the retailer for an RMA – do not open the board if it voids warranty. For a custom build, add a PCIe Intel or Realtek 2.5GbE card in any x1 slot or use a USB 3.0 to 2.5GbE adapter as a temporary workaround. Keep your purchase invoice and motherboard serial number ready, as support will ask for them to authorize replacement.
FAQ
Ethernet shows “Unidentified Network” but Wi-Fi on same router works – is the PC broken?
Not necessarily. This almost always points to a driver or DHCP issue rather than hardware failure. Link lights being on means the port has power and a physical link. Follow Fix 3 to install the vendor LAN driver, then Fix 6 to release and renew the IP. If ipconfig /all stops showing a 169.254 address and shows a gateway like 192.168.1.1, the hardware is fine.
Should I disable Wi-Fi to make Ethernet work?
You do not need to disable Wi-Fi permanently, but Windows prioritizes the adapter with the lowest metric. To test cleanly, turn off Wi-Fi temporarily: click the Network icon in the taskbar > Wi-Fi > Off, or go to Settings > Network & internet and toggle Wi-Fi off. Once Ethernet shows Connected and you can browse, you can re-enable Wi-Fi. Ethernet will remain the preferred path for traffic when both are on.
Device Manager shows no Ethernet adapter at all – where did it go?
It is either disabled in BIOS or the driver failed to enumerate. First check BIOS as in Fix 4 and enable Onboard LAN. If enabled, power off, unplug the PSU switch for 30 seconds to fully drain residual power, then boot and reinstall the LAN driver from the motherboard support page. If it still does not appear after both steps, the controller may be faulty.
Why is my new PC only getting 100 Mbps on a gigabit plan?
Check three things. First, the cable: you need at least Cat5e in good condition and under 100 meters. Cat5 cables often cap at 100 Mbps. Second, the router port: some ISP routers have one 2.5 Gbps port and three 100 Mbps ports – try another port. Third, the setting: right-click Ethernet > Status and look at Speed. If it says 100 Mbps, go to Device Manager > Advanced > Speed & Duplex and ensure it is set to Auto Negotiation or 1.0 Gbps Full Duplex, then reseat the cable.
