My wired internet worked normally until about a week ago, then suddenly stopped. The Ethernet port on the PC no longer lights up. I tested multiple cables and router ports, and they work correctly with another computer and an Xbox. I also bought a UGREEN USB Ethernet adapter, but that does not work on this PC either; the adapter and cable work fine on other devices.
I have already tried flushing DNS, releasing and renewing the IP address, restarting the PC and modem, resetting network adapters, disabling the proxy, reinstalling both the motherboard LAN and UGREEN adapter drivers, and testing several USB ports. An IP reset briefly restored the connection for about 20 seconds, but it stopped again and now neither Ethernet option shows any activity. What should I check next to determine whether this is a Windows, USB, motherboard, or hardware power issue?
3 Answers
Since the same cables, router ports, and USB adapter work on other devices, the problem is probably limited to this PC rather than the network. Check Device Manager for disabled or failed network devices, including hidden devices, and look for warning icons. Also check the adapter's Properties and make sure Windows is not disabling it to save power. If possible, boot from a Linux live USB: if Ethernet still does not work there, that strongly points to a motherboard, USB-controller, or other hardware problem rather than Windows.
Try a full power reset, not just a normal restart: shut Windows down, turn off the power supply, unplug the PC, hold the power button for about 15 seconds, wait a minute, then reconnect everything. Some onboard controllers can remain stuck after a crash or power event. If the adapter still works on other machines but neither it nor the motherboard port works on this PC, a clean Windows reinstall or live-USB test can separate software corruption from a hardware fault.
The fact that the built-in port has no link lights is important. DNS flushing and renewing an IP address cannot fix a missing physical link, so focus on whether the network hardware is being detected at all. Enter the BIOS/UEFI and confirm the onboard LAN controller is enabled, then load the motherboard's chipset and LAN drivers from the manufacturer's support page rather than relying only on Windows. For the USB adapter, check whether Device Manager refreshes when you unplug and reconnect it; if it never appears, test with a powered USB hub or check whether the PC has a broader USB issue.
Related Questions
Lenovo Thinkpad Stuck In Update Loop Install FilterDriverU2_Reload