My iPhone 4s not connect to PC?

I have tried 3 different cords now, and they all work fine when I put them in a wall charger and charge my phone, but when I put the cords into the computer, nothing happens, it doesn't even show that my iPhone is connected to my computer… I'm currently running iOS 7.1.2, so that may be the problem, because it's always worked fine before, even with a messed up cable I used to have… Please help!

EDIT: It also may be the newest iTunes as well, because I believe I have synced my iPhone to computer with iOS 7.1.2 installed on it…

It could be that the port inside your 4s is not clean (preferably)