Originally Posted by Freebase Dali

If it's a router, wireless or otherwise, and you were fine connecting wirelessly but now you can't connect with the wired connection, ask whether the router has MAC address filtering. If it does, this basically requires any device connected to it, wirelessly or not, to have their MAC address entered into the "allow" list. Since your wireless network card and your wired network card are two separate physical entities, and MAC addresses are physically dictated on the device and are unique, you will have a different MAC address for each. And if only your wireless network card's MAC address is allowed, then obviously your wired one won't be.

If this is the case, you will have to get whoever manages the router to add your wired network card's MAC address to the allowed list in the router. You can find this mac address by doing an IPCONFIG /ALL in a command prompt.