Wi-Fi doesnt works with 3.1 or 3.0 updates! Fix this ASAP!!

The 3.1 and 3.0 updates dont let me use wi-fi it says that i'm not connected when the wi-fi is on. i've already restored my iphone through the computer, restored from the phone and even started new but the problem continues. all of this started since 3.0 when it didnt connect sometimes but with 3.1 its worse because it doesnt connects at all. plz fix this asap because some apps cant be downloaded through edge or 3g! thats all thnx! btw its an iphone 3g