I'm an expat living in China for the time being. I bought a used iPhone 3G 16g. When I plugged in into my computer to synch with itunes,calendars etc... it wiped everything back to nothing. A window on my computer screen told me that I did not have a SIM card in the phone. But I did. It also told me that I needed to activate the phone. There is not AT&T or other service providers that you have to sign up for here. I brought the phone back to the store that I bought it from and he got it working again but they say I shouldn't plug it into my computer. I need to synch to my computer to communicate with it. What should I do? Rediculous as it may sound. This is my first smart phone. So not savy to of what the deal is. Please let me know if you have any answers. Thanx, Alec