General :: Phone Suddenly Turned Off And Won't Turn Back On?

I bought an HTC First a few weeks ago ( I think lol) and love it so far. So earlier today at school I was on my phone, and nothing was wrong. I put it in my pocket and about 20 minutes later I pulled it back out and it was dead. Odd, because it was almost full before. So I thought, whatever I'll charge it at home. So after school I put it on charge and the red light wasn't blinking. I gave it around 30 minutes and still nothing. It's been a few hours and still, it isn't charging or turning on. I tried holding power/vol+/vol- for more than 2 minutes. I have warranty but HTC said if I send it in I'll be forced to pay to replace the screen too, which has a TINY crack on the corner .