sounds to me like the Ethernet interface died.
Any recent thunderstorms or power issues?
I once saw a thunderstorm take out an entire network in a home, Multifunction device , VoIP devices, Ethernet ports on computers, Wireless access point, etc.
If you have (coaxial) cable internet make sure the cable is grounded, to a GOOD ground like a copper ground rod!
If you have DSL make sure you have a Lightning suppressor on the line and that it is grounded, to a GOOD ground like a copper ground rod!
the above items are fundamental and people often assume that because the cable company or telephone company installed it, it must be good. telcos and cable companies often ground to cold water pipe but that is not always good enough. But maybe they grounded it to a cold water pipe which worked 20 years ago, but when that pipe burst in your basement a few years ago the pipe was replaced with PVC or some other non-conductive material. Maybe the cold water pipe was just a poor ground to begin with.
The other thing might be that if something else on your LAN burned up it could also sed a surge down the ethernet line.
My point is look on your own front porch first