Xperia z weird display problems topic

I have been using my Xperia z for about a year and everything was great until recently I have experienced weird problems. Now my power button is not working I can't lock my phone and I have to wait for screen to sleep. Now the weirdest problem is that when I wake up the screen (by pressing the volume button) the display is not responding at all just like it appears that touch screen has been disabled. When I reset my phone it all got to normal but then again if the screen went to sleep than it will never be responding and I have to reset my phone again and try not to lock the screen.

Help What is wrong with my Xperia??