will not connect to any wifi

There are several solutions out there. I suggest you google it. they range from software issues, to bad antenna issues, to board issues. First try>reboot, if that doesnt work try>turning on airplane mode>reboot>turn off airplane mode, if that doesnt work try >Settings>General>Reset>Reset Network Settings, It seems there was an issue that cropped up with IOS 5, as a next to last resort you could try updating your software(IOS 7.0.4 will be your only option here unless you are able to restore from a previous backup on itunes. This option may however give you more grief than it fixes, if other peoples experiences are to be believed.) The last resort is to get a replacement if you have warranty left.

If it is the "board" know this replacing the board is the same as getting a DIFFERENT phone. it will have to be activated on your network, it will have whatever size memory it has, and used iphone 4s models go for as much as $275 or more on ebay, but then again if you find one that works for you you can sell your old one for nearly as much, plus you have the option of keeping your old chassis if you get one that has a broken glass.