If you can't delete an ISO file as the file is open in your System, check if it is mounted as a drive or not. Uses these proven fixes to resolve the issue.

If you cannot delete a file or a folder on an NTFS file system volume in Windows, follow the solutions mentioned in this post to resolve the issue.

Why Cant I Delete, Edit, or Rename a File That Is in Use? Windows prevents you from deleting, moving, or renaming files that are in use to keep your computer system stable.

Fire up process explorer and find the file is in use by, wait for it, Windows explorer. So Windows Explorer can't rename/move my file because it's in use by itself.