Macbook Pro 15" 2011 Display problem diagnoses?

So I was using Chrome one day and a few other programs then this problem happens. It also seems to happen when I play League of Legends sometimes and forces me to restart the computer. The mouse still moves but nothing is clickable, my cap locks still works so it appears as if the hardware is fine. I took it to the repair shop and they checked everything and said it's all showing up green and couldn't find anything wrong with it. I did a forum check and believed it was Google Chrome messing up my display with a possible flash conflict or something but I just uninstalled it and it's happened again twice in the space of 2 minutes. Here's a picture...

I figured it could also be related to overheating since my laptop does tend to get hot quite a lot or it could be a combination of problems so I'm baffled.

Has anyone else been having these types of problems or have a possible diagnoses?