I was using my iPhone 4 normally today (I did reboot it once, but it still ran fine after that). Put it in my pocket after surfing the web, pulled it out a few minutes later to check something on the web and it was black (and not responding). I would think this was the battery, but it was basically fully charged. I have tried: -Holding home and plugging in iTunes. -Tried entering DFU mode. -Tried RecBoot. -Tried holding home and power for about 2 minutes. No response. I have tried multiple cables and computers (both desktops and laptops). No response from iTunes, nor does any computer even register a device is being connected. It seems like it is fully a brick. It seems like a power problem...but I doubt a battery would just croak. Also, I get no response even after plugging it in to charge for hours.