you will get clue when you search for them.
"My Computer\HKEY_CLASSES_ROOT\*\shellex\ContextMenuHandlers" is the 1st place.
If they appear when you right-click folders and drivers, you will need to go "My Computer\HKEY_CLASSES_ROOT\Directory\shellex\ContextMenuHandlers" and "My Computer\HKEY_CLASSES_ROOT\Folder\shellex\ContextMenuHandlers"
Best search them to delete from all the places.
Good luck, new friend from Shanxi.