Android apex problems?

Well I've had the phone for about a week. I have never had a touch screen before. This is the first time it died on me. I went home to charge it, and was watching videos on you tube. Suddenly half way thru a video it made a pop noise and then the screen went blank. I couldn't get it to turn back on. It was hot, but I've had phones get mcuh hotter. I took the battery out and let it set for a half hour. I gave up trying to turn it back on. I put it all back together and suddenly it just started up. The charger was in at that point tho I had tried it several other times in my desprate attempts to try and get it started again. I don't have a lot of apps. And emulator and gtunes and some others. What the hell just happened to my phone?