I have an iPhone 3Gs I got from a guy off Craigslist as an add-on to something else I was buying and it won't read a SIM card. I opened the phone and all 6 of the copper pins in the SIM reader slot are there. It's currently stuck on the iOS setup and when I put in a SIM card, the top left says "Searching..." and iTunes says I have to insert a SIM card before I can move on. I don't know what to do because the reader looks perfect. Help please?