After opening another window (no mods) screen blanks out, went white

So, someone with more computer skills, please help. I had been playing the game, all normal etc and no I don't have mods installed, never have. I had saved the game, thankfully. And opened Google, I had to do something, only took about half an hour. I thought I'll just leave the game open and on Managed worlds. So when I was done, closed Google and this white screen is all I could see. Tried to close the game, couldn't because no menu or anything would show up. I had to use task manager to close the game. 

Is this the game crashing, a bug or just something else. I have uninstalled and reinstalled the game and this is a new save, so I don't understand. 
Photo attached