my iphone 4s can't connect to any wi-fi.,

I need your help., I've been trying to connect to any network using wi-fi but i can't.. I tried to reset my phone like a hundred times already., i even tried restoring my phone.. I've deleted everything including media and apps.... 😟 please help... its been 1 month and im really frustrated coz i just bought my phone last may 2012 .. 😟