USB wifi keys have become a $10 item now. First thing I'd do is turn the radio in the computer off and plug one of the $10 kind in and see if that made a difference.
i just had a similar issue with my windows 7 laptop.... i have been connecting to my mums wifi for months and all of a sudden my laptop wouldnt pick up THAT ssid... it would get all the other ones in the area but not my mums.... strangely my iphone could get on it and so could my other laptop which was sitting right next to me... i opened a connection through my iphone hotspot and went into windows updates>OPTIONAL DOWNLOADS> and installed the optional updates for wlan etc.... once update was done i simply disconnectioned from my iphone hotspot and like magic my mums ssid appeared and my laptop automatically connected to it.... i hope this helps anyone else having an issue, might i suggest restoring hidden updates too to make sure u r not missing any important files....
