How to Fix Ethernet Not Working

Ethernet not working means a wired connection that fails to carry traffic, which is a different problem from a wireless drop or a full network outage. The fixes below go in order from the cable outward to a BIOS setting, and you should check the link after each one, because a single fault usually accounts for the whole dead connection. The aim is a restored wired link without replacing the network card.

What Causes Ethernet Not to Work?

Ethernet not working is caused by a break in the wired path or a disabled component between the computer and the router. The four most common causes are below, ranked from most to least frequent on Windows.

How Do You Fix Ethernet That Is Not Working?

Work from the physical cable outward and check the link light after each step, stopping as soon as the connection returns. The steps move from the cheapest, most common fault to the rarest.

• Check the link lights and reseat the cable. Look at the LED beside each Ethernet port. Unplug the cable from both the computer and the router, then push it back in until the RJ45 clip clicks. A solid or blinking light at both ends means the link is live.
• Try another port and another cable. Move the cable to a different LAN port on the router or switch, then swap in a known-good cable rated Cat 5e or higher. This isolates whether the fault is the cable, the port, or the computer.
• Enable the adapter. Press Windows plus R, type ncpa.cpl, and press Enter. Right-click the Ethernet adapter and select Enable if it is greyed out. A disabled adapter shows no connection at all.
• Update or reinstall the driver. Open Device Manager, expand Network adapters, right-click the Ethernet controller, and choose Update driver. If a yellow warning icon remains, choose Uninstall device and restart so Windows reinstalls it.
• Run ipconfig release and renew. Open Command Prompt as administrator and run ipconfig /release, then ipconfig /renew, then ipconfig /flushdns. This fixes a live link that carries no traffic because of a failed DHCP lease.
• Test the cable on another device. Plug the same cable into a second computer or laptop. If it works there, the fault is inside the first machine; if it fails everywhere, the cable or the router port is the problem.

Check the Cable and Link Lights First

Inspecting the cable and the port link lights confirms whether the physical wired connection is live, which is the first check for any dead Ethernet link. The lights sit beside the Ethernet port on both the computer and the router.

1. Confirm the cable clicks fully into the port on both the computer and the router.
2. Look for a solid or blinking link light at both Ethernet ports.
3. Treat a dark link light at both ends as a cable, port, or adapter fault.
4. Reseat the cable at both ends and watch for the link light to turn on.
5. Run the cable along a different path away from power cables to rule out interference.

Try Another Cable and Port

Swapping the cable and the port isolates whether the fault is in the cable, the router port, or the computer, which a single change cannot reveal. A spare cable and a second port give a fast comparison.

1. Replace the Ethernet cable with a known-good cable rated Cat 5e or higher.
2. Move the cable to a different LAN port on the router or switch.
3. Connect the cable to a second device, such as a laptop, to test the same cable and port.
4. Note whether the link light returns after each change.
5. Treat a working link on the second device as a fault on the first computer, not the cable.

A cable that works on a second device but not the first confirms the fault is inside the first computer. A cable that fails on every device confirms a damaged cable or a dead router port. The RJ45 connector is a common failure point, so check that its locking tab is intact and that the copper pins are clean.

Enable the Ethernet Adapter in Network Connections

Enabling the Ethernet adapter restores a connection that shows nothing because the adapter was switched off in Network Connections. A disabled adapter appears greyed out in the connections list.

1. Press Windows plus R, type ncpa.cpl, and press Enter to open Network Connections.
2. Find the Ethernet adapter in the list.
3. Right-click the adapter and select Enable when it appears greyed out.
4. Right-click the adapter again and select Diagnose to run the network troubleshooter.
5. Confirm the adapter status changes to a connected network name.

If the adapter is already enabled, disabling it and enabling it again often clears a stuck state after a Windows update. An adapter that shows a red X has no cable signal, which returns the check to the cable and port. An adapter missing from the list entirely points to a driver or a disabled onboard LAN.

Update or Reinstall the Ethernet Driver

Updating or reinstalling the Ethernet driver replaces corrupt code that prevents the wired adapter from forming a working link. Device Manager lists the wired adapter under Network adapters with the controller name.

1. Right-click the Start button and select Device Manager.
2. Expand Network adapters and find the Ethernet or LAN controller.
3. Right-click the adapter and select Update driver, then Search automatically for drivers.
4. If a yellow warning icon remains, right-click and select Uninstall device, then restart so Windows reinstalls the default driver.
5. Download the latest driver from the motherboard or PC maker when the link stays dead.

A wired adapter marked with a yellow warning icon in Device Manager confirms a driver fault. The motherboard maker publishes the correct LAN driver for the onboard Realtek or Intel controller, which resolves faults the generic Windows driver does not. Save that driver to a USB drive first if the computer has no other way online.

Renew the IP Address and Flush DNS

Renewing the IP address and flushing DNS restores traffic when the wired link is live but a failed DHCP lease left the adapter without a valid address. All of these commands run in an elevated Command Prompt.

1. Type cmd in Windows Search, right-click Command Prompt, and select Run as administrator.
2. Run ipconfig /release to drop the current wired IP address lease.
3. Run ipconfig /renew to request a fresh address from the router DHCP server.
4. Run ipconfig /flushdns to clear the stored DNS records.
5. Run ipconfig /all and confirm the Ethernet adapter shows a valid IPv4 address and gateway.

If a renew still leaves the adapter stuck, reset the network stack with netsh winsock reset and netsh int ip reset, then restart. A wired adapter showing a 169.254 address after a renew reached no DHCP server, which returns the check to the cable, the port, or the router. A valid 192.168.x.x address with a matching gateway confirms the lease and the physical link both work.

Set the Network Speed and Duplex to Auto

Setting the adapter speed and duplex back to auto-negotiation fixes a dead or dropping link caused by a forced speed the adapter and switch do not share. The setting sits on the Advanced tab of the adapter properties.

1. Open Device Manager and double-click the Ethernet adapter.
2. Open the Advanced tab.
3. Select the Speed and Duplex property in the list.
4. Set the value to Auto Negotiation.
5. Click OK and confirm the link returns at the negotiated speed.

A link forced to 1.0 Gbps Full Duplex on one end and auto on the other can fail entirely. Auto-negotiation lets the adapter and the switch agree on the highest shared speed, which is 100 Mbps or 1 Gbps on most home networks.

Enable the Onboard LAN in the BIOS

Enabling the onboard LAN controller in the BIOS restores an Ethernet adapter that is missing from Windows because the firmware disabled it. The setting sits in the onboard devices section of the BIOS or UEFI.

1. Restart the computer and press the BIOS key, often Delete, F2, or F10, during boot.
2. Open the Advanced or Onboard Devices section.
3. Find the Onboard LAN, Integrated NIC, or LAN Controller setting.
4. Set the value to Enabled.
5. Save and exit, then confirm the Ethernet adapter appears in Device Manager.

A computer with no Ethernet adapter listed in Device Manager and no driver fault points to a disabled onboard LAN in the BIOS. A USB-to-Ethernet adapter restores a wired link when the onboard controller has physically failed. If the wired path stays dead after every step, the steps to fix no internet connection cover a wider outage, and the guide to fix Wi-Fi that keeps disconnecting covers the wireless alternative.

Ethernet Not Working Symptoms and Likely Causes

Last Thoughts on Ethernet That Is Not Working

Ethernet that is not working is resolved by reading the port link lights first and then working from the cable outward to the BIOS, checking the link after each step. No light at both ports is a physical fault, so reseat the cable, try another port, and test the same cable on another device before opening any setting in Windows. Once a link light is on, enabling a greyed-out adapter, updating the driver, and renewing the IP address with ipconfig clear most of the remaining faults without new hardware.

A wired connection is one of several faults a computer can hit, and the same ordered approach applies across them. The hub page listing common PC problems connects every troubleshooting topic, and readers who want to understand the standard itself can review the explanation of what Ethernet is.

Key Takeaways:

• Read the port link lights first; no light at both ends usually means a cable or port fault, and no software fix will help.
• Reseat the cable until the RJ45 clip clicks, then try another port and another known-good cable.
• Test the same cable on a second device: if it works there, the fault is in the first computer, not the cable.
• Enable a greyed-out adapter in Network Connections with ncpa.cpl; a disabled adapter shows no connection at all.
• Update or reinstall the driver when Device Manager shows a yellow warning icon, and run ipconfig /release and /renew for a live link with no traffic.
• A missing adapter points to a disabled onboard LAN in the BIOS or a missing driver.

Frequently Asked Questions (FAQs)