I purchased a new NIC which is Intel Gigabit CT PCI-E Network Adapter EXPI9301CTBLK.
I plugged in PCI-Ex slot, and then I booted the system. But it does not detect the new network adapter. The device manager only shows the on-board network adapter, but does not show the new PCI-Ex network adapter.
When I plug the ethernet cable into the new network adapter, I can see the light of the adapter flashing/blinking. But there is not internet connection.
I downloaded and installed the newest drivers but it is still not working.