Computer turning downs internet for all devices

have you tried a different cable - using a different port on the router

whats the make and model of the pc
i would update the ethernet drivers


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Uninstall and allow windows to re-install the adapter and Driver
goto the device manager > Network Adapters > click on the [+] to show all the adapters

right click on the ethernet adapter and from the menu

remove/uninstall the adapter

Now restart the pc and allow windows to detect new hardware and re install the adapter and the driver
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