About a week ago my iPhone 3G turned off, completely, and won't turn back on for love nor money... It doesn't seem to be the battery having run out, charging it for hours doesn't have any effect, and it doesn't show the low battery logo when trying to power it up. It also doesn't register when plugged into my MacBook Pro or any other computer (as in, it doesn't even show up as a USB device in System Profiler). It hasn't received any physical damage or anything, and I've taken it apart and it seems to be a-ok on the inside, no loose connectors or broken components. The phone is nearly two years old and has been running relatively problem free until now. Has anybody got any ideas on what could be the matter, or even better, how to fix it? Thanks!