Network card (also called network interface card and short for NIC) is an expansion card which installs into a computer and enables that computer to physically connect to a local area network. The card provides an interface to the media. 

The Network Interface Card must be working for your PC in order to be able to communicate on a network. When network problems occur, the NIC is less likely to be the cause than infrastructure such as cables, routers and hubs. The following problems show you are undergoing some failure of network connectivity.

When we reinstall a computer, we cannot find the net card drive:

1. If your net card supports the PNP function and the version of your programming system is beyond Windows 95/98,the system will recognize and drive your net card automatically.

2. If the net card does not support the PNP function because of the compatibility problem,the computer still can check the net card.Just set it up by choosing one compatible net card drive.

3. If the ways above are still useless,you have to open the mainframe-box,see your original net card drive.and find the brand and model,which later you can surf and download on the net.

Fix that there is no light on the NIC with the cable connected properly

1. Unplug and replug the network connector into the NIC and at the other end.

2. Check that the other end of the cable is connected to a device that is powered on.

3. Try switching the cable to a different port if available.

4. Try a different network cable.

5. Check the control panel in Windows to make sure the card is recognized and working.

Fix failed connection to network with the lights on the NIC :

1. Make sure that other network devices are powered on.

2. Make sure that your PC is configured with the proper Work group or Domain name.

3. Check that your PC is not using an IP address that is already in use on your network.

4. Make sure that your PC is not using a name that is already in use by another PC on the network.

5. Allow up to 20 minutes for network polling to identity all available resources.

6. Check the network cable connections and use a different port if available.

7. If Windows is configured for more than one NIC,make certain that the correct one is being used for this network.

The data collision light is frequently or continuously lit. 

1. Check the network cable. It should be connected to the proper port, and you can try a different port for testing.
2. Check the IP address. Ensure that your PC is not using an IP address that is already in use on your network.

3. Check the user name. Your PC can not be using a name that is already in use by another PC on the network.