It has a lot of possiblilities on why you're WIFI is not working anymore. First pull up device manager and see if your Wireless LAN is listed with drivers on it.
This happened to me - turns out it was a hardware failure., the WiFi card appears to be near where the power supply enters the laptop and pressure on the case would make the card fail and the WiFi stop working.
I ended up returning the laptop to sony for repair - been brilliant since I got it back.
United Kingdom
