Standard, unflashed/non-rooted S2, fully charged last night, just pulled it out of my pocket and it won't turn on. Only have a usb cable with me not a main charger, so tried plugging it in to that, nothing. No battery charge screen or anything. Tried pulling out the battery, waiting a bit then turning it on, nothing. Tried power+home+vol down and still nothing. No vibration, no screen, nothing, just won't turn on. Phone was slightly warm until I pulled the battery out. Any ideas?