Wonder if anyone can answer this one.
I have a Samsung S3 on the Three Network in the UK. Been working absolutely fine since getting it in Sept 2012. On Christmas Day I wake to find the phone cycling between the Samsung Start up screen and the Three Network logo every thirty seconds or so and then restarting. As it was on silent there was no sound or vibrate. Kept repeating this until I switched it off. Switched back on to no avail. Still kept doing the same thing. Pulled battery, left off for an hour - tried to restart, exactly the same. Cycling between the Samsung Start up screen and the Three Network logo. Hadn't dropped the phone, or any damage. On Xmas Eve, plugged it in as normal, Xmas morning woke up and it was cycling its wee heart out.
Tried a soft reset. Nothing. Came back on and still going backwards and forwards between the two screens.
Tried a factory reset, Now this changed everything. Screen now black. No screen activity at all. Nothing. Non responsive. Cant see or do anything, cant hear anything, no vibrate. When plugged into charge the LED is red, when switched on (no sound or vibrate) the LED comes on after 5 seconds goes blue and pulses gently for around 30 seconds then goes off. Starts again, off for 5 seconds, gently pulses for around 30 seconds and switches off.
Tried Kies to no avail as the phone switches itself off before the cable connection is done.
The phone wont switch off with the power button, the battery has to be removed to power down. Once battery is reinserted power button has to be pressed before starting up again.
Anyone got any ideas cause its stumped me.