My wired internet worked normally until about a week ago, then suddenly stopped. The Ethernet port on the PC no longer shows any link light. I confirmed that the cables and router ports work by testing them with another computer and an Xbox. I also bought a UGREEN USB Ethernet adapter, but that does not work on this PC either, even though the adapter works with the same cable on a laptop and Xbox.
I've already tried flushing DNS, releasing and renewing the IP address, rebooting the PC and modem, switching cables and router ports, resetting the network adapters, disabling the proxy, reinstalling both the motherboard LAN and UGREEN adapter drivers, and trying different USB ports. Releasing and renewing the IP briefly restored the connection for about 20 seconds once, but it stopped again. What else could be preventing both the built-in Ethernet and USB adapter from working?
1 Answer
Since the same cables, router ports, and USB adapter work on other devices, this probably isn’t a cable or router problem. Check Device Manager for disabled devices or warning icons, and look in the adapter’s Properties to make sure it is enabled. Also check the BIOS/UEFI settings to confirm onboard LAN hasn’t been disabled.
Because both the motherboard port and a separate USB adapter fail only on this PC, the issue may be Windows networking, a USB/chipset problem, or something affecting the operating system rather than the Ethernet hardware. Try booting from a Linux live USB or Windows installation/recovery environment and test the adapter there. If it works outside your normal Windows installation, repair or reset Windows; if it still fails, check the motherboard, USB power, and BIOS settings.
The lack of a link light is important. DNS flushing and IP renewal only matter after the adapter establishes a physical connection, so they won’t fix a dead link. Check whether the adapter appears at all in Device Manager and whether its status says the device is working properly.