I have a homebuilt PC, and I've had it for about a year now. I had successfully used ethernet before, but I have not for about four months now. Now when I try to connect via ethernet, my computer does not in any way detect that there is anything connected. Other PCs work with my router and modem, as well as the modem separately, and I have tried several brand new ethernet cables.
My motherboard is an ASRock P67 Pro3 SE, running Windows 7 64-Bit with an HD6870 and an i3 2100.