If you read through the Tutorial of a Repair Install, you'll see that you should skim through the Windows.old folder to see if there's anything you still need and, if not, delete it to free up some lost space.
It doesn't appear there is anything installed that looks suspicious enough to merit why your machine is still acting up. At this point, I would save all of my game data and go with a complete clean reinstall. It sounds like we're going to end up going down multiple rabbit holes since nothing is pointing to a source of the problem by now. It's hard to say how or why this occurred when I wasn't there when it started to try and somehow link the result to the cause.