hide application in task manager o

There are many ways. One possibility is to convert your code to run as a service (system service but not web service), and I think there are articles in this web site that describes services.
 
Note that if you are installing this into another person's system, then they can undo it; it is a matter of how technical they are.

Hi,

check this article will help

http://www.c-sharpcorner.com/UploadFile/satisharveti/customizedtaskmanager04172007035418AM/customizedtaskmanager.aspx