PowerPoint OLE automation without making the window visible

Hai ::

 In The Powerpoint Application I want To Find out the Ole objects . PowerPoint OLE automation without making the window visible.I make the  ShowWindowsInTaskbar  also visible  false.But still the Power Point application was shown to the User.Any body have idea Regarding that

This Code am used

PowerPoint.Application pptApp = new PowerPoint.Application();

                        PowerPoint.Presentations objPresentations = pptApp.Presentations;

                        PowerPoint.Presentation objPresentation;

                        //SetWindowLong((IntPtr)pptApp.HWND, GWL_EXSTYLE,

                        //GetWindowLong((IntPtr)pptApp.HWND, GWL_EXSTYLE) | WS_EX_LAYERED);

                        pptApp.WindowState = PowerPoint.PpWindowState.ppWindowMinimized;

                        pptApp.Visible = MsoTriState.msoTrue;

                        pptApp.ShowWindowsInTaskbar = MsoTriState.msoFalse;

                        //TaskbarList.TaskbarList tblc = new TaskbarList.TaskbarList();

                        //tblc.HrInit(); // got to call this before we can do anything with the interface

                        //tblc.DeleteTab(objApp.HWND);

                        strFID = Guid.NewGuid().ToString();

                        ToolFile = GetFileElement(ref ACRSXml, ref  Doc, ref strParentFID, ref strFID);

                        ToolVersionXml.AppendChild(ToolFile);

                        //insert File Into DataBase

                        strFileName = Doc.GetAttribute("File");

                        objPresentation = objPresentations.Open(strFileName, MsoTriState.msoTrue, MsoTriState.msoFalse, MsoTriState.msoTrue);