Assuming you are using windows 7; Click the windows icon on the bottom left, right click computer, click properties
In the links to the left click Device Manager.
In the list of devices look for Network Adapters, unbranch it, see if the Make/Model for the device is listed.
Make sure it doesn't have a red X or yellow ! symbol on it and it should be okay.
If you like you can take a screenshot of your device manager and post it here and we can tell you more.