I was running my phone perfectly fine, and when I turned off the phone to replace the battery, it won't turn back on at all. The Samsung logo just loops repeatedly, and I can't get into Recovery mode at all. I can get into download mode, (sort of), by the conventional means, but when I press volume up to confirm download mode, I can't do so. The phone hangs for a second, and then restarts its self. Is this SDS? How do I get it fixed? I am in the USA, and I have a SGS III i9300. My phone information is below in my signature.