Protocol and Hardware Tests

It is prudent to run some simple commands to ascertain whether the card is really bad or something else is wrong. Open a command prompt. (Swipe up on the Start screen and select "All apps." From the Windows System section, select "Command Prompt.") Next, type the command "nslookup" and press "Enter." If the connection is fine, you will see something like this:

Default Server: cdns01.comcast.net
Address: 75.75.75.75

This means the computer is getting out to the Internet to a dynamic name server. If the server cannot be found, your connection with DNS is bad due to a misconfiguration, the DNS server is down, or your connection with anything beyond your laptop is broken, in which case your NIC could be broken. You can check your network connection from the "Network and Internet" area of your Control Panel where your connections are listed. Here, your network may be listed under the "No network access" section.

Checking Both NICs

Before you consider one of the NICs to be broken, first make sure wireless connectivity is switched on. A wireless button is usually located under the screen; switching it on causes a blue LED to light, indicating a wireless connection. You can tell if an NIC card is bad by going to the Control Panel, selecting the "Hardware and sound" link and then choosing "Device Manager." Expand "Network Adapters" and double-click either of the NICs listed. A window will appear indicating whether the device is working properly.