Multiple problems with Ethernet connection

Yes, everything seems to be fine after I installed the new NIC. It says #2 because I forgot to uninstall the first (onboard) NIC's driver beforehand.
The Device Manager now shows 2 Ethernet adapters. Is it possible to uninstall an onboard NIC? Or should I just leave it?

One final thing: the NIC is using Windows' generic drivers. I tried to install the driver on the disc that came along with the NIC, but the net started to fail, so I rolled back the driver because I didn't have time to investigate.

Edit: I tried installing another driver again, this time from the manufacturer's website. The driver actually works fine, but Auto Negotiation of Speed & Duplex sets it to 100Mbps, which then causes my computer to fail to connect, producing an IP address of 169.254.94.255.

I tried to manually set it to 100Mbps (both Full and Half Duplex), but neither of them worked. I had to set to 10Mbps in order for the connection to be successful. My router is Netgear WPN824v2, and supposedly it's capable of 10/100Mbps connections.

Can you disable onboard NIc in BIOS? Otherwise you can disable it in device manager. It even that fails... in "network centre"-> adapater settings.

Post relevant device manager output otherwise. If special drivers won't work... use the generic win7 one