IPhone 5 will no longer connect to Wi-Fi?

I have an IPhone 5 that was not updated when iOS 7 was released. If this is the problem, please tell me. It has always connected to the Wi-Fi before and has not for the past 2-3 weeks. It does connect to the Wi-Fi where I work, however. Please simplify directions for I'm not very tech savvy.

You must go to setting> Wi-Fi> and set the Wi-Fi up. Most of the time, it defualts to a Wi-Fi that is open, but not all of them are.