Open only one instance of Windows Calculator
                            
                         
                        
                     
                 
                
                    Dear Friends,
  
 I have opened a windows calculator on the click of a button on my web  application but the moment i again click on the same button again, an  another instance of the windows calculator opens again.
  
 How can i ensure that only one instance should be opened at a time.
  
 Thanks
  
 Varun Sareen