Implement Licensing in Windows Forms Application so that it cannot be installed on multiple machines

 have created a windows application & it uses Microsoft reporting services. i am using vs2008 for the development i need to deploy the application at clinets system whts the best & safe method can we create any security check / licesence so that the application cant not be executed in other systems is Code Access Security for ClickOnce Applications helpful?? i was trying with systen mac add to provide licesencing which is the best method to ptovide with licesening