You don't say what operating system you are running, but assuming you have Windows Vista, Windows 7, or Windows 8, go to Control Panel and run "Network and Sharing Center". When that window opens up click on "Change Adapter Settings" at the upper left of the window. The Adapter window will list all network adapters you have on your computer. If you already have a wireless network adapter then one of them will say "wireless network adapter". If not, then you will need to buy one. Basically, a wireless network adapter, either internal to the PC or a USB device, is a radio transmitter/receiver.