Short for Network Interface Card, the NIC is also referred to as an Ethernet card and network adapter. It is an expansion card that enables a computer to connect to a network; such as a home network, or the Internet using an Ethernet cable with an RJ-45 connector.
Due to the popularity and low cost of the Ethernet standard, most new computers have a network interface build directly into the motherboard.
NIC cards serve as conduits between a computer and a network (like Internet). They translate the data on the computer into a form that is transferrable via a network cable and control the data as it is sent to other devices on the network.
There are three different types of NIC arrangements, or configurations: jumper, software and the newest technology, Plug-and-Play (PnP).
Jumper configurable NIC cards are efficient and easy to use for older equipment. They have physical jumpers (small devices that control computer hardware without the need for software) that determine settings for the interrupt request line, input/output address, upper memory block and type of transceiver.
Software configurable NIC must be manually configured when installed, but contain a proprietary software program that allows the operator to configure the NIC via a menu, or choose the auto configuration mode that determines what configuration is most suitable.
Most NICs today use the PnP technology as it does not have to be manually configured, though it can be. PnP NICs will auto-configure upon installation during the system boot-up sequence, but can cause conflicts with the hard drive.
Put simply, a network interface card enables a device to network with other devices. This is true whether the devices are connected to a central network (like in infrastructure mode) or even if they're paired together, directly from one device to the other (i.e. ad-hoc mode).
However, a NIC isn't always the only component needed to interface with other devices.
For example, if the device is part of a larger network and you want it to have access to the internet, like at home or in a business, a router is required too. The device, then, uses the network interface card to connect to the router, which is connected to the internet.
All hardware devices need device drivers in order to work with the software on the computer. If your network card isn't working, it's likely that the driver is missing, corrupted or outdated.
Updating network card drivers can be tricky since you usually need the internet in order to download the driver, but the driver issue is precisely what's preventing you from accessing the internet! In these cases, you should download the network driver on a computer that works and then transfer it to the problem system with a flash drive or CD.
The easiest way to do this is to use a driver updater tool that can scan for updates even when the computer is offline. Run the program on the PC that needs the driver and then save the information to a file. Open the file in the same driver updater program on a working computer, download the drivers and then transfer them to the non-working computer to update the drivers there.