I found an extended disk clean up in the tutorials of the seven forums which also works on windows 8. I kept the "previous windows installation(s)" box unchecked.
As I kept all files and settings, would checking the box mean they will all get deleted in the clean up??? Or does it clean up something else from win7 which is useless?? I don't have a windows.old folder so if it's just that then it's ok.
It's usually for the Windows.old folder and any left over conflicting files from the OS you upgraded from or after a refresh of the current Windows 8. Sometimes the Windows.old folder is hidden. If the size for Previous Windows installation(s) is in the GBs, then the it may be hidden.
It's safe to check Previous Windows installation(s) to delete all of these files if you do not want them, and would like to free up the HDD space it's using.