This tool will show all help files which are registered in the system registry. This will allow you to see which are orphaned.

Click the "Find" button to begin scanning the registry. Once this is complete, any orphaned entries will automatically be placed at the top of the list so you can see them.

Those entries whose corresponding file is no longer in the location specified in the registry (or even on your hard disk) are displayed with a cross icon. You can select these orphaned entries and press the "Delete" button to delete them from the registry.

You can attempt to reconcile an orphaned help file entry by using the "Edit" button. Here you can type in the path where the file resides (if it still exists at all). You can use the "Browse" button to help select a folder where the file might exist, or better still use the "Search" button to locate all matching files (if any) on the drives you specify. Any matches will be listed and you can select which you think is the correct file.

"When deleting a reference whose file still exists, delete the file also"
Set this option if you wish to delete a help file along with its reference in the registry. This is not advisable for novice users. Some files may not be deleted depending on their nature.