It sounds like something came loose - the pressure on the keyboard is putting the screen connector in better contact and so on.
As you're careful, you should be able to take it apart to check.While not as 'easy' as a desktop, you should be able to take apart your laptop to fix it, with sufficient care, and fairly simple tools
The service manual is essential and tells you what you need and how to take it apart. You probably want to read through the parts for keyboard and display replacement. Open it up, make sure the connectors are secure (removing and replacing them sounds good) and arn't worn out or damaged in any obvious way, and put it back together.