A friend of mine has an almost new TP-Link router. It worked fine with a wired connection to his PC XP desktop and WiFi connection to new apple laptop for a few weeks.

Recently though the wired internet connection stopped working, but WiFi still works fine from the apple laptop. Neither the apple laptop nor the PC desktop work when plugged directly into the router, with different cables.

My conclusion is the Ethernet ports on the router have somehow failed. Can anyone think of what else it could be?