Latest update broken my phone!!!

First I had the greyed out messages which was annoying but not disastrous however this morning all I did was close some screens and download three songs and then my messages went unresponsive now my keys are unresponsive and my buttons! I can't get into my phone because I can't enter the pass code and the phone won't turn off via the buttons. It has crashed several times today but it boots up the same! It's ridiculous!!! What can I do?!