iPhone won't connect to computer.
I have a windows PC, ITunes is installed and up to date, PC is up to date. I plug my IPhone5s in and it sometimes says "USB device not recognized", sometimes it charges. But never connects. It fails to "install new device" when I plug it in. I have tried 2 different cords, neither are Apple certified but it has never been a problem with my previous phone. I bought this IPhone from a friend who I'm pretty sure "found" it. What steps can I take next?
iPhone 5s, iOS 8.3