1. Is your wireless router connected to the internet - do you see the light that says it is connected?
2. When you start the laptop, does it show a wireless network has been detected? You should see a small icon in the system tray at the bottom right of your screen.
3. When you click in this icon does it show your wireless network there?
4. If you select the network and click on 'Connect' what happens?
Forget about the message that says a network cable is unplugged, it isn't important right now. Please just answer those questions.