As root try "iwlist scan", if that doesn't show anything when there should be a network in range, then type "dmesg" into the terminal to get a list of the kernel messages, if there is something wrong with the wifi, there may be something related there, probably at the bottom if you have just done a scan.

If you don't get any information from those commands, then you might want to try a reflash, if it still isn't working after a reflash, it is probably hardware.