Computer doesn't recognize Ethernet cable

Maybe this is a temporary issue which should be resolved after you restart the computer.

If your computer doesn't recognize ethernet cables, it is possible that the network card/adapter (or Ethernet) is disabled.

If you are not sure how to enable it, check out the don't know how to enable/disable the network adapter solutions to learn how to enable the network card/adapter.

If you didn't manage to make the computer recognize the Ethernet cable from the router, it is possible that the router itself is damaged. If you determined that there is nothing wrong with the Ethernet cable and if you tried plugging in the cable in a different port, but nothing changed, replace the router.

Maybe the network card is disabled in the Device manager. In order to enable it, follow the steps below:

1. Go to the start menu and type Device Manager (in the search box - If you use Windows 7)
2. Expand the Network adapters section and locate the network card.
3. Right-click on the network card and select Enable.

Maybe the Ethernet cable isn't plugged in the router's Ethernet port, firmly. All you need to do is to plug it in, firmly, in one of the YELLOW ports as the blue one is the Internet "intake" port.

Note: Once the cable is detected by the computer, a green light near the ethernet port should start blinking.

Maybe the Ethernet cable is bent (or cut) or the Ethernet connector is damaged. Before you decide to buy a new one, try plugging in the cable in another computer.

Note: If the cable is recognized by another computer, but not by yours, check out the other solutions.

Consider this as a last resort, only if you are sure that the computer's Ethernet port and the Ethernet cable are functional.

If the computer's Ethernet port is dirty, it won't detect the Ethernet cable you plugged in. All you need to do is to take a small piece of cotton (or a cotton bud), pour some isopropyl (rubbing) alcohol on it and clean the Ethernet port.

If your modem stopped being detected by the computer (or router) after a lightning struck, contact the operator, because the modem might have malfunctioned and needs to be replaced.

If the Ethernet cable is fully functional and firmly plugged in on both ends (computer's and router's), but your computer doesn't recognize it, restart the router by unplugging it from the power outlet and plugging it back in after a few minutes.

Maybe only the port in which the Ethernet cable is plugged in is damaged. If you have other unoccupied ports in the switch, which are still functional, plug the cable in one of them.

If you don't have the appropriate network card driver installed in your computer, the ethernet port won't work, i.e. your computer won't recognize the ethernet cable which is plugged in it. All you need to do is to to install the appropriate driver and the problem should be resolved.

If you don't know how to find, download and install appropriate drivers, check out the don't know how to download and install drivers guide.

If your computer doesn't recognize the Ethernet cable from the router, it is possible that the router is turned off. Check the router's lights. If none of the lights blinks, then the router is definitely turned off.

All you need to do is to turn on (or plug in its adapter in a power outlet) and the issue will be resolved.

If the main Ethernet cable from the ISP was plugged in directly in your computer, and it stopped detecting the Ethernet cable after a lightning struck, and you did everything else to resolve this issue, including contacting the ISP, but without success, buy a new network adapter, because the Ethernet port of your motherboard is very likely damaged, and probably beyond repair.

If the Ethernet port(s) of the switch is (are) dirty, the computer won't detect the Ethernet cable. All you need to do is to take a small piece of cotton (or a cotton bud), pour some isopropyl (rubbing) alcohol on it and clean the Ethernet port(s).

Note: If the indicators next to the port, which signal when a connection between two devices is established, don't blink after you have cleaned them, check out the other solutions.

If the router's Ethernet port(s) is (are) dirty, the computer won't detect the Ethernet cable. All you need to do is to take a small piece of cotton (or a cotton bud), pour some isopropyl (rubbing) alcohol on it and clean the Ethernet port(s).

Note: If the indicators next to the port, which signal when a connection between two devices is established, don't blink after you have cleaned them, check out the other solutions.