How to close the pdfcreator process?


I am facing an issue with the tool as the process is still running even after I close the object in my .net code. the process is removed only when I exit my application. however, I am running my code as a service, and hence the process is running continuously. Is there any way I can close the process without using the kill command on command shell?
here is a sample code I used for testing.
      static void startclosePdfcreator()
            m_PDFCreator = new clsPDFCreator();
             string strParam = “/NoProcessingAtStartup”;

             m_PDFCreator.cStart(strParam, true);
             m_PDFCreator = null;
In debug mode, even after executing the last line of the code, the process is still showing under task manager.
I am using version 1.1 and 1.7.3