First of all, is the connection a cable connection to the property?
If it is Virgin would have placed a small black modem, presumably in her flat which is connected to the cable. It has an RJ45 Ethernet connector, which looks slightly wider than an RJ11 normal telephone modem connector. If your friend has bought a wireless router as well this will be connected to the ethernet port.
It would be handy to know what make and model it is. Post Back with details.
If the wireless router is on, your computer needs to be wireless enabled to receive the signal. What make and model of computer do you have and is it wireless enabled?