Hi, I have an unlocked 3G iPhone and I'm using it with a O2 SIM card. Sometimes when I received a call I lost the coverage and the words No service appeared at the top left corner of the screen but after few seconds I recovered the coverage and everything was back to normal. But this is the second time it happens to me that after the words No service and after a few minutes the iPhone goes to dead. Black screen, iTunes does not recognize it, it is not possible to charge it. I have tried to reset it by holding both top power button and home button together for a few seconds and it is still the same. The icon of the apple (with a bite on it as it is unlocked) appears but nothing else happens. First time it happened to me I brought it to the 'shop' in which I got it unlocked and, after deleting all my data, they got it to work again. Right now I cannot go to the shop and I would really need to keep my data. Any idea? Thanks in advance.