I was scared off attempting to use it when, one day I was doing something in a terminal and it locked up. I was clicking all over the screen to try and bring up

I was scared off attempting to use it when, one day I was doing something in a terminal and it locked up. I was clicking all over the screen to try and bring up the task manager (or any response), when the phone called my other phone! Input must have been going through to other apps but the screen was showing a blank terminal.