nothing has changed, it will connect wirelessly but not through the ethernet
Sorry, but I must disagree. If it worked, now doesn't something has changed.
If both ethernet & wireless were previously working.
You should check your router's settings to make sure it's accepting connections on all those types, not just N.
Look at site for the router's IP address and default login/pass.
It sounds to me like the router is operating only in N, which isn't compatible with a, b, or G. or vice versa
N has multiple input and outputs (MIMO), a/b/g does not, which causes the incompatibility.