Why can't I turn on my phone?

I was doing a home work from school, I need phone for that because i need to take pictures of something. I have password on my phone, but then when I press the lock button suddenly it didn't work. I thought that it was only temporary. Then i waited like around an hour, nothing happened. So, i tried to turn it on by pressing the lock button but nothing happened too. I took off my battery, plugged in to my PC, smacked it, nothing happened. I don't know what to do. Help please?