It exist in two areas I'm having the same issue trying to rid myself of this application . It will be in this path of your files
( This pc , windows c , program files ( x86 ) , HP , Diagnostics , PSDR )
Also it is located in ( This pc , windows c , program files , HPPrintScanDoctor ) . For me when I go to delete because there is no uninstall option . It just keeps saying it is unable to uninstall because it is in use by another folder ???