How to Fix Ethernet Not Working: Step-by-Step Troubleshooting

When Ethernet stops working on a gaming PC, the fastest fix is usually to reseat the cable at both ends, try a different port on the router or switch, and restart the PC and router. If the network adapter still shows “Network cable unplugged” or no connection, work through the driver, adapter, and BIOS steps below, from easiest to hardest.

Symptoms: What “Ethernet Not Working” Can Look Like

The phrase covers several different failures, and sorting out which one you have saves time. Common patterns include:

• The network icon shows a red X or “Network cable unplugged” even though a cable is attached.
• The icon shows “Unidentified network” or “No internet” while the link light on the port is lit.
• The connection works for a few minutes, then drops during gaming or large downloads.
• The adapter is missing from Device Manager or Network Connections entirely.
• The link negotiates at a very low speed, such as 100 Mbps on a connection that should be gigabit or faster.

The first two symptoms point to physical or addressing problems. The third often points to a bad cable, a power-saving setting, or a failing port. The fourth points to a driver, BIOS, or hardware fault on the motherboard.

Likely Causes, Ranked

1. Cable or port problem. Loose connectors, a damaged cable, or a dead port on the router or switch are the most common causes.
2. Router or modem glitch. A device that has been running for a long time can stop handing out addresses.
3. Driver issue. A corrupted or outdated network driver, or a driver reset after a Windows update, can disable the adapter.
4. Disabled adapter or power-saving setting. The adapter can be turned off in Windows or put to sleep by energy-saving options.
5. IP or DNS configuration. A wrong static address or a stale lease leaves the PC connected but unable to reach the internet.
6. BIOS or UEFI setting. The onboard LAN controller can be disabled in firmware.
7. Hardware failure. The onboard controller or the port itself can fail, which is less common.

Step-by-Step Fixes

1. Check the link lights. Most Ethernet ports have a small light or pair of lights next to them. If neither light is on with a cable plugged into a powered router, the problem is physical.
2. Reseat the cable. Unplug and firmly plug the cable back in on both ends until the connector clicks. Look at the plastic latch; a broken latch can let the connector sag out of contact.
3. Swap the cable and the port. Try a different cable, ideally one known to work on another device, and move to another LAN port on the router or switch. Cat 5e, Cat 6, and Cat 6a cables all carry gigabit speeds at normal home lengths. Cables with a kinked or crushed section should be replaced.
4. Restart everything. Power the PC off, then power-cycle the router and modem according to the maker’s instructions, wait a minute or two, and start them again before the PC.
5. Test the cable on another device. Plug a laptop into the same cable and port. If the laptop works, the fault is in the PC. If it does not, the fault is in the cable, port, or router.
6. Run the Windows network troubleshooter. Open Settings, go to Network and Internet, and use the troubleshooter for network problems. It can re-enable a disabled adapter and renew the IP address.
7. Enable the adapter. In Network Connections, check whether the Ethernet adapter is shown as disabled. Right-click it and choose Enable if needed.
8. Renew the IP address. Open Command Prompt as administrator and run ipconfig /release followed by ipconfig /renew. If the problem is name resolution, ipconfig /flushdns clears the cache. If the adapter has a manually entered address, switch it back to automatic unless your network requires a static one.
9. Reset the network stack. Windows includes a network reset option in the network settings. It removes and reinstalls adapters and returns network settings to defaults, so note any custom settings such as VPN or static addresses first.
10. Reinstall or update the driver. In Device Manager, open Network adapters, right-click the Ethernet controller, and choose Uninstall device, then restart so Windows reinstalls it. If it does not return, download the LAN driver from the motherboard maker’s support page for your exact board model. Many boards use Intel or Realtek controllers, and the maker lists the supported driver on the board’s support page. If the PC has no internet at all, download the driver on another device and transfer it on a USB drive.
11. Turn off power saving on the adapter. In the adapter’s properties under Advanced and Power Management, settings such as Energy Efficient Ethernet, Green Ethernet, and “Allow the computer to turn off this device to save power” can cause dropouts on some systems. Disabling them is a common step for random disconnects.
12. Match the link speed. In the adapter’s Advanced tab, the Speed and Duplex setting is normally Auto Negotiation. If a flaky cable forces a low speed, a replacement cable is the better fix than forcing a setting.
13. Check the BIOS or UEFI. Restart and enter firmware setup using the key shown on the boot screen. Look for an onboard LAN or network controller option; the menu name and location vary by motherboard maker, so check the board’s manual. Make sure it is enabled. Changing firmware settings can cause instability, so change only this setting, and consider that a BIOS update, if the maker lists one that mentions LAN fixes, should follow the maker’s instructions closely because a failed update can leave the board unusable.
14. Try a USB or PCIe Ethernet adapter. If the onboard port is dead but everything else checks out, an add-in adapter can restore wired networking while you decide on repairs.

Quick-Reference Table

Problems Specific to Gaming and VR PCs

Gaming and VR setups are sensitive to dropouts. A wired link that disconnects for a second can kick a player out of a match or break a wireless VR stream that depends on a stable connection to the router. If you use a headset that streams from the PC over WiFi, the PC should be wired to the router, so a flaky Ethernet link affects the headset too. Check that cables are not pinched behind a desk or run alongside power cables for long distances, and avoid tight bends near the connector.

If you use a switch between the PC and the router, test with a direct cable to the router to rule out the switch. Some motherboards ship with 2.5 Gb Ethernet; a 2.5 Gb port still negotiates down to gigabit on standard cables, so a drop to a slower speed than expected is a cue to check the cable and the other end of the link.

When to Stop and Contact the Maker or a Technician

Stop troubleshooting and contact the motherboard or PC maker, or a qualified technician, in these cases:

• The port is physically damaged, with bent pins or a cracked housing.
• The adapter does not appear anywhere, the BIOS setting is enabled, and an add-in adapter works perfectly, which points to a failed onboard controller.
• The PC is under warranty and you would need to remove parts to continue. Opening the case or flashing firmware can affect coverage depending on the maker’s terms.
• You smell burning or see damage near the rear I/O panel.

For any step that involves the inside of the PC, such as seating an add-in network card, shut the system down, switch off the power supply, and unplug the power cable first. Never open a power supply; leave that to the maker.

Prevention Tips

• Use good quality, undamaged cables and replace any with bent latches.
• Keep the motherboard LAN driver current from the maker’s support page, and apply updates deliberately rather than from random driver packs.
• Avoid sharp bends and tight clamps on the cable.
• Restart the router periodically if it shows signs of instability, and keep its firmware updated per the maker’s guidance.
• Keep a spare short cable for quick swaps when troubleshooting.

Frequently Asked Questions

Why does my PC say the cable is unplugged when it is plugged in?

The adapter is not detecting a link. A damaged cable, a loose connector, or a dead router port is the usual cause. Swapping the cable and port, and checking that the link light turns on, will tell you whether the fault is outside the PC.

Can a driver update fix Ethernet that has stopped working?

Yes, when the cause is a corrupted or mismatched driver. Reinstalling the driver from the motherboard maker’s support page for your exact model is more reliable than a generic driver tool. If the adapter still does not appear, the cause may be in the BIOS or the hardware.

Should I disable Energy Efficient Ethernet?

It is a common troubleshooting step when a wired connection drops randomly. The setting saves a small amount of power, and turning it off has no real downside for a desktop gaming PC. If the drops stop, you have found the cause.

Is it safe to change LAN settings in the BIOS?

Enabling the onboard LAN controller is a simple change, but firmware changes can cause instability if you alter other settings by accident. Change only what you need, and consult the motherboard manual for the menu name, since it differs between makers.

When should I switch to WiFi or an add-in adapter?

Use WiFi only as a temporary fallback, because it is more exposed to interference and latency spikes. A USB or PCIe Ethernet adapter is the better stopgap for gaming if the onboard port has failed.