I have a very similar issue. I was able to connect to my WPA2 network once when I first tried, but now I am unable to connect to any wireless network. The Wifi radio is on. When I go to the Wi-Fi settings window under Settings and bring up the menu to select Scan, I don't see any networks display even though I know there are multiple around (and I can see them from my laptop).
Are you still able to connect to your network and view others when you scan? What do you think could be my problem and is there anything else I can try?