The answer is simply: Dud has been designed by the software developer to replace annoying executables and programs that are started by the Windows operating system or applications. Mentioned are files like helpctr.exe or stobject.dll which are not useful to most users or necessary at all.

The developer has created a second program called Replacer which can be used to replace protected files in operating systems such as Windows XP or Windows 2000. It can for example also be used to replace the annoying googleupdate.exe, ctfmon.exe and basically any other annoying process that gets automatically started by the operating system or software programs.

It might make more sense in certain situations to find a way to disable the process or service so that it does not get started at all but this is sometimes not possible. That’s where a program like Dud comes in very handy.