iphone 4S stopped working when fully charged and it will not turn on. what should i try?

I have gone through the exact same issues - my iPhone 4S stopped responding completely - the back felt hotter than usual - I held down the power and home buttons together and then had to do a complete restore of my iPhone, losing everything that I'd added the last 10 days. I will visit the Genius Bar this weekend about a replacement, although I have been by already once and they claimed that there was not a battery issue with my phone...

My earlier post was the same issue. I called apple care and we did some trouble shooting and nothing worked. They sent me a new phone.

Thank you Sammy! My phone stopped working all of a sudden. I had not dropped the phone down. Did try holding the power button - didn't work, home button for some time - didn't work. Kept in charge for 15 mins - didn't work. The phone started heating. My previous phone once had this problem - it was kept in car (sunny day) and the phone switched off. Later when it came to room temperature it worked. Tried the same with iPhone 4S - still didn't work. Was worried and checked for apple discussions and it turned out to be lucky. I had not held the home and power button together. This time tried that and it worked fine... If any of your phone is not working and you had not dropped it, don't panic. Try some of the methods in discussions and it'll fix it. Especially when your phone has worked for more than a year without troubles.