Iphone 3g wi fi problem

[Bebsy]

I have a Iphone 3G. I have lost wi fi for about a year on it. It has never been Jailbroke. It has only been connected to Itunes. I have taken it to different apple stores with no luck. I have been told the airplane mode may have caused it by apple and others. If you go into setting and look under wifi it shows no wifi. Shows to be inactive as not an option. You cant turn it on or change the wifi setting. Can anyone help?

Thanks ahead of time!