I have a drive that i reinstalled windows 7 (did not erase the drive) on and then upgraded to windows 10 and back to 7 and now the windows.old file is gone and it is taking up a chuck of space (100 gigs or so) so how do i find the windows.old folder?? Its a 600gb hatachi 5400rpm drive and after i installed win 7 there was about 400gb left