Recently, I had this problem whereby my laptop (Vaio - Intel Core i5) is unable to connect to my home Wi-Fi. The weirdest thing is that I am able to access the Internet at home using my iPad as well as my smartphone.
For a day I was unable to use the Internet to get my assignments going. It kept showing "No available network connections" and also "Please turn on the Wireless Switch" in the Vaio Smart Network box. It was frustrating.
Well, after Googling for a bit, I found out what's wrong.
Somehow, I accidentally off the switch situated near the mouse pad, the place where there're yellow lights -- the Power light as well as the Wireless light. What you got to do is to move the switch from OFF to ON.
That's it. Simple right?
Hope this helps.