Please feel free to skip the background and read the problem. Background: I have an iPhone 3Gs that was getting poor battery life. It was one from my father after he upgraded. I am pretty tech savvy, graduated with BSEE from Purdue University with a lot of lab experience, and thought I could replace the battery myself with one from an iPhone 3G that was still working. I watched a few videos on YouTube about disassembling the iPhone and replacing the battery, so I tried it myself. I was able to successfully swap the batteries of the 3Gs with the 3G and both devices powered ON when I was finished. I let the phone charge overnight, it worked properly, and my alarms went off this morning for work. This is when I ran into The Problem. The Problem: I don't know exactly when this started happening, but it was within the 1 hour time period from when I woke up (and unplugged the charger) until I got in my car to come to work. The iPhone 3Gs was not on when I got into the car. I tried to turn it on and nothing happened. I plugged it into the USB port in my car (the one I was using to listen to music yesterday) and I saw the apple logo for about 2 seconds, then it would turn off, then the apple logo for 2 seconds, and off again. It continues to reboot no matter what button press sequence I perform. When I unplug the device from the USB port, it stops rebooting and does nothing. Solutions I have tried: - I have tried to reset the device by holding the power and home button for about 10-15 seconds with the USB plugged in and it continues to reboot as I mentioned above. - I have tried to reset the device by holding the power and home button for about 10-15 seconds with the USB UNplugged and it doesn't respond at all. - I have tried to put it into DFU mode by holding the power button for 8 seconds, then holding home button without releasing power for 8 seconds, then releasing power but holding down home for 8+ seconds with the device UNplugged and it still does not respond. I am not able to connect to iTunes until I get home today, which is where I am going to start. I was hoping that there might be something that I am missing, or a whole different route all together. Thank you in advance for all of your future help, and I will update as I see progress.