My S5 is about four months old. It has worked great until today. Around 1 pm I noticed that my screen had a decidedly green tint to it. I have no idea why. Then around 4 pm I noticed that the screen doesn't work at all any more. I've removed and replaced the battery, per all the videos on YouTube, with no improvement. Whenever it starts up, the menu and return soft buttons to the left and right of the home button blink on and off many times before becoming solid. Any ideas? The phone is unusable...