My father asked me to “fix his laptop”, I looked at it and wasn’t able to tell if it was windows 10 or 8 or Vista. It has become some strange hybrid somehow with telling different things in the different parts of the OS. Also the styling would be different at the different parts of the OS(The windows menu looks like 10 but the window decorations are like Vista etc.). He had some professional software that wants to keep so I didn’t dare to do a fresh install or clean up, left it as is. He is still using it just like that.