which is likely what is needed I am going to ask if by any chance you just re-installed the operating system to discover the NIC no longer working?
If such is the case try installing the motherboard drivers now and see if it starts working.
If not then replacing the NIC with a paddle card is the fix you need.
I have a problem with my computer - ethernet port don't work. This is an integrated Ethernet port in motherboard.
Ethernet light won't light. The network card disappeared from device manager. There's just "Microsoft Kernel Debugger". In BIOS "On-Chip MAC Lan" is set at Auto. I'm using Windows 8 Pro. I don't want to buy a ethernet port when there's a possibility of repairing this one.
My motherboard: GIGABYTE M61PME-S2
Pictures of my computer inside: http://tinypic.com/a/2trm0/4
Can anybody help me, please?