I'm not sure that my computer has a WiFi card. How do I check?

On Windows 7 or Vista? Go to the go the Start Menu > Control Panel. Then, in the top right of the Control Panel, open the View dropdown menu. Then, select Category > Network and Internet > Network and Sharing Center.

If your device has a WiFi adaptor, you'll see a 
Change adapter settings option.

On Windows 8?
Go to the App screen and swipe or scroll to the right. Then, select Windows System category > Control Panel. Then, in the top right of the Control Panel, open the View dropdown menu. Then, select Category > Network and Internet > Network and Sharing Center. If your device has a WiFi adaptor, you'll see a Change adapter settings option.

On Windows XP? Go to the go the Start Menu > Control Panel. Then, in the top right of the Control Panel, open the View dropdown menu. Then, select Category > Network and Internet > Network Connections > Wireless Network Connection. You should see your WiFi adaptor listed.