Screen enlarges screen saver and doesn't allow me to log in.

This happened a few days ago and I charged it and pressed the buttons and finally got it to work again. It happened again today and I haven't been able to get it to work. Obviously it isn't the kind of phone where you slide off the battery cover, remove it and let it reset. Could this be caused by too many hours of video games? I don't actually "talk" on it much, just some texting, photos and lots of games.

I can press the button and get the "voice" to play music.