froze then it wouldnt turn on how to fix

i was on an app and my tab froze so i let it die and then charged it once it was dead. (i coulnt turn it off cuz it wouldnt so i had no choice) this happened a secound time on the same app so i did the same thing and deleted the app. the next day i was using another app and i had to go do something so i pressed the power button once and left. when i came back it wouldnt turn on i tried chargeing it but it still wont come on. i tried to hold the power and volume button thing but that didnt work and i dont know how to take out the battey. pls help