Opeing non mdi form

Hello Experts , Good Morning 
I have created a feestru form in c # . From the same form I have Report button on the form . From there I am running the report preview form . The code for the  Report Button is 



 this.Hide();
            rppreview rppreview = new rppreview();
            rppreview.Show();
         

 1] this code loads rppreview form finely . But it run the form as MDI form .
 2] When I close the rppreview from I want to again load my feestru form . The code for loading again the feestru from is 

             this.Close();
            feestru newMDIChild = new feestru();
            // Set the Parent Form of the Child window.
            newMDIChild.MdiParent = this;
            // Display the new form.
             newMDIChild.Show();
Please Help , Thanks in Advance 
regards
anand kulkarni