Wireless not working....help!!!

Hi,

Recently bought a Belkin wireless router for use with a Virgin cable modem. I installed the router on my laptop and set up the wireless network. However, I can only pick up the internet when the networking cable is plugged in from the router to my laptop. However, my housemate can pick up and connect to the network wirelessly, even when I unplug the networking cable from my laptop. I've got a new wireless card, so I know it works....but I can't detect our network (my card picks up several other networks though).

On installing the router, I selected to connect via the cable rather than wirelessly...is this the reason why? I've tried re-installing the router, but it hasn't given me the option to connect wirelessly anymore...if that makes sense.

Any help would be greatly appreciated!!!