Clear open window

I'm getting an open window from time to time on my desktop and when it's there there is nothing showing it's open in task manager. I've recently reset my PC and this was one of the problems I was having before I reset it and it's still comes up. It seems to happen when I open a program or just after a close one' it doesn't seem to be a specific program. The window is clear and when I put my mouse over it my courser shows It's thinking.  
  funny pc image.jpg (Size: 120.94 KB / Downloads: 33)