My S5 is about 4 weeks old & I've had no problems so far. Today when at about 35%power., I plugged it in to charge. 10 minutes or so later, there was a purple haze to the screen which then went black. I've had no response since, it won't switch on at all. I've tried taking out the battery & SIM & putting them back in again with no luck. Does anyone have any idea what to do next?